CN109256794B - Converter for synchronous wind power generation system - Google Patents
Converter for synchronous wind power generation system Download PDFInfo
- Publication number
- CN109256794B CN109256794B CN201710567986.4A CN201710567986A CN109256794B CN 109256794 B CN109256794 B CN 109256794B CN 201710567986 A CN201710567986 A CN 201710567986A CN 109256794 B CN109256794 B CN 109256794B
- Authority
- CN
- China
- Prior art keywords
- level module
- phase
- level
- unit
- alternating current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000001360 synchronised effect Effects 0.000 title claims abstract description 75
- 238000010248 power generation Methods 0.000 title claims abstract description 66
- 230000005284 excitation Effects 0.000 claims abstract description 41
- 238000013461 design Methods 0.000 claims abstract description 4
- 238000004804 winding Methods 0.000 claims description 46
- 230000005611 electricity Effects 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims description 2
- 238000012546 transfer Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 16
- 238000001514 detection method Methods 0.000 description 6
- 239000003990 capacitor Substances 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 238000013178 mathematical model Methods 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Images
Classifications
-
- H02J3/386—
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/14—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field
- H02P9/26—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices
- H02P9/30—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices
- H02P9/305—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices controlling voltage
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P2101/00—Special adaptation of control arrangements for generators
- H02P2101/15—Special adaptation of control arrangements for generators for wind-driven turbines
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P2103/00—Controlling arrangements characterised by the type of generator
- H02P2103/20—Controlling arrangements characterised by the type of generator of the synchronous type
-
- 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
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
The invention provides a converter for a synchronous wind power generation system, comprising: the acquisition unit is used for acquiring real-time operation data on the three-phase synchronous generator; the control unit is used for receiving the data sent by the acquisition unit and generating at least a converter trigger instruction; the three-level module unit group is used for rectifying alternating current provided by the three-phase synchronous generator according to a trigger instruction sent by the control unit and outputting alternating current of a first grade, each three-level module unit group connected with each three-phase synchronous generator comprises at least one three-level module unit, the three-level module unit groups between the phases are connected in parallel, and the three-level module units contained in the three-level module unit groups are connected in cascade. The converter provided by the invention can meet the requirements of 6KV, 10KV and even higher voltage, and the power of a single machine is improved. The invention can also realize the control of excitation according to the design parameters of the system and can be compatible with the permanent magnet synchronous generator by simplifying the circuit.
Description
Technical Field
The invention relates to the field of wind power generation, in particular to a converter for a synchronous wind power generation system.
Background
With the shortage of energy, wind power generation is more and more focused, and because wind energy is a clean renewable resource and the abundance is huge, the proportion of electric energy generated by wind power generation to the total amount of world power generation is increasing day by day, and the technical improvement of wind power generation becomes the hot point of research, wherein a converter can directly influence the efficiency of wind power generation. Therefore, the converter is particularly important for a wind power generation system.
However, the current transformer in the current market can only meet the requirement of a power grid below 3KV basically, and cannot meet the current domestic higher and more mainstream voltage grades (6KV and 10 KV).
Disclosure of Invention
The invention aims to provide a converter for a synchronous motor wind power generation system, which comprises:
the acquisition unit is connected to a three-phase synchronous generator and a power supply grid and is used for acquiring real-time operation data on the three-phase synchronous generator and grid-side voltage and grid-side current on the power supply grid;
the control unit is connected with the acquisition unit and used for receiving the real-time operation data of the three-phase synchronous generator, the network side voltage and the network side current sent by the acquisition unit and generating at least a converter trigger instruction according to the real-time operation data, the network side voltage and the network side current;
the three-level module unit group is connected to the three-phase synchronous generator, the control unit, the excitation winding and the multi-winding transformer, and is used for controlling and converting the changed alternating current of the three-phase synchronous generator according to a trigger instruction sent by the control unit, and outputting the alternating current with fixed frequency and a first level after rectification and inversion;
the three-level module unit group connected with each phase of the three-phase synchronous generator comprises at least one three-level module unit, each unit of the module unit group comprises a three-phase alternating current part and a single-phase alternating current part, the three-phase alternating current part is connected with the transformer, and the single-phase alternating current part is connected with the synchronous motor after being cascaded. The single-phase part is connected to a three-phase stator winding of the generator after being connected in cascade; in particular, for an electrically excited synchronous generator, a special three-level power unit is also connected to the excitation unit, the output of which is connected to the excitation winding of the generator;
and the multi-winding transformer is connected with the three-level module unit group and used for converting the alternating current of the first grade output by the three-level module unit group into the alternating current of the second grade and outputting the alternating current to the power supply network side.
According to one embodiment of the present invention, the three-level module cell groups between phases are connected as follows:
and second alternating current input ends of the three-level module units of each first stage are mutually connected.
According to an embodiment of the present invention, the three-level module units included in the three-level module unit group are cascade-connected as follows:
and the first alternating current input end of the three-level module unit at the previous stage is connected with the second alternating current input end of the three-level module unit at the next stage.
According to an embodiment of the present invention, the three-level module unit group and the multi-winding transformer are connected as follows:
and the alternating current output end of each three-level module unit in each phase of three-level module unit group is connected to the multi-winding transformer.
According to one embodiment of the present invention, the three-level module unit group and the three-phase synchronous generator are connected as follows:
and the first alternating current input end of the last stage of the three-level module unit group of each phase is connected with the three-phase alternating current output end of the three-phase synchronous generator in a one-to-one correspondence manner.
According to one embodiment of the invention, the control unit is in communication connection with the central control platform and receives a control command of an operator to determine whether to send a trigger command.
According to another aspect of the present invention, there is also provided a synchronous wind power generation system, the system comprising:
a three-phase synchronous generator for generating electricity;
a current transformer as claimed in any one of the preceding claims.
According to one embodiment of the invention, the three-phase synchronous generator is a permanent magnet synchronous generator.
According to one embodiment of the present invention, the three-phase synchronous generator is an excitation synchronous generator, wherein the excitation unit includes:
the three-level module converts the first-level direct current output by the direct current output end of the first-level three-level module unit in the first-phase three-level module unit group into second-level alternating current;
the resonant circuit module is used for generating resonance to transfer energy;
the high-frequency transformer module is used for converting the second-stage alternating current into third-stage alternating current;
the uncontrolled rectifying module is used for converting the third-stage alternating current into fourth-stage direct current;
the output LC module is used for filtering the output voltage; and
and the chopping module is used for releasing energy through the chopping path when the direct-current voltage is overhigh.
According to one embodiment of the invention, the control unit sends a trigger instruction to the excitation unit to trigger the excitation unit.
The converter provided by the invention has the advantages that the converter can be suitable for the requirements of 6KV, 10KV and even higher voltage, and the power of a single machine is improved. In addition, the invention also provides an excitation control solution, which can realize the control of excitation according to the design parameters of the system. Moreover, the invention can be compatible with the permanent magnet synchronous motor by simplifying the circuit.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a block diagram of a synchronous wind power generation system employing a converter topology of the prior art;
fig. 2 is a block diagram of a synchronous wind power generation system employing a converter implemented by a three-level module unit group according to an embodiment of the present invention;
fig. 3 is a block diagram showing the internal connection details of the three-level module cell group in the converter shown in fig. 2;
FIG. 4 shows an equivalent circuit diagram of d and q axes of a prior art excited synchronous generator;
FIG. 5 is a block diagram of a synchronous wind power generation system for outputting a voltage of 6KV class implemented by a three-level module unit group according to an embodiment of the present invention;
FIG. 6 is a block diagram of a synchronous wind power generation system for outputting a voltage of 10KV level implemented by a three-level module unit group according to an embodiment of the present invention;
FIG. 7 is a circuit schematic of a diode-clamped three-level modular unit employed in one embodiment in accordance with the present invention;
FIG. 8 is a circuit schematic of an excitation unit employed in an embodiment in accordance with the invention; and
FIGS. 9-10 are flowcharts illustrating operation of a wind power system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
Description of the drawings: the first ac input terminal of the three-level modular unit mentioned herein corresponds to the terminal a similar to the third diagram, and the second ac input terminal corresponds to the terminal b similar to the third diagram.
Fig. 1 is a block diagram of a synchronous wind power generation system using a converter topology according to the prior art. As shown in fig. 1, 101 denotes an electrically excited synchronous generator, 102 denotes a motor-side converter, 103 denotes a grid-side converter, 104 denotes a double-winding transformer, and 105 denotes a dc chopper circuit.
The system comprises a motor side converter 102, a grid side converter 103, two direct current side filter capacitors, an electric excitation synchronous generator 101, a grid side converter 103, a transformer, a grid side converter 103, a grid side filter capacitor, a grid side transformer, a grid side filter capacitor and a grid side filter capacitor, wherein the three-phase alternating current end of the motor side converter 102 is connected with the electric excitation; in addition, the direct current chopper circuit 105 is further included, the direct current chopper circuit 105 is connected in parallel to a direct current bus of the grid-side converter 103, and the motor-side converter 102 and the grid-side converter 103 generally adopt a traditional two-level converter.
The two-level converter comprises power diodes and power devices of a controllable switch, and 3-phase bridge arms with the same structure are provided, and each phase of bridge arm comprises two IGBT (insulated gate bipolar translator) power devices with anti-parallel diodes. Since the single IGBT device is limited by voltage and current at present, the converter power of the topology is generally less than 2 MW. There are two conventional solutions: firstly, the output current is increased by connecting the devices in parallel; second, the motor is modified to a multi-winding motor, with each converter connected to one winding of the motor. Both methods add complexity to the system and inherently have a lower output voltage, with lower voltages and higher currents at a given power, which increases cable cost and loss.
Although the above converter can meet the requirements of 660V and 690V voltage levels. However, with the rapid development of science and technology, the voltage classes of 660V and 690V are far from meeting the requirement of high-power occasions such as offshore wind power generation, and therefore, a converter meeting the high voltage class is urgently needed in the market at present.
Fig. 2 is a block diagram of a synchronous wind power generation system employing a converter implemented by a three-level module unit group according to an embodiment of the present invention. As shown in fig. 2, the synchronous power generation system 200 includes an acquisition unit 201, a control unit 202, a generator module 203, a three-level module unit group 204, a multi-winding transformer 205, a power supply grid 206, and an excitation unit 207. The excitation unit 207 may be selected according to actual conditions.
The acquisition unit 201 is connected to the generator module 203, and is used to acquire real-time operation data of the generator in the generator module 203, and grid-side voltage and grid-side current on the power supply grid 206. In the present invention, the acquisition unit 201 includes a current sensor. Typically, a current sensor is placed at the ac output of the generator to detect real-time operating current data of the ac current at the generator output. In addition, the current sensor can also be placed at the power supply grid side for detecting the real-time current data of the power supply grid.
However, the present invention is not limited to the above-mentioned current sensor as the collection unit for collecting data, and in fact, a voltage sensor may be used to detect the operation data of the power generation, and in general, a voltage sensor may be placed at the ac output terminal of the power generator to detect the voltage data at the output terminal of the power generator. In addition, the voltage sensor can also be placed on the power supply grid side to detect the real-time voltage data of the power supply grid. In addition, the voltage sensor can also be placed in the middle direct-current link of the converter to detect the voltage data of the converter.
The power generation system further includes a control unit 202 connected to the acquisition unit 201 for receiving the real-time operation data, the grid-side voltage and the grid-side current of the generator module 203 sent by the acquisition unit 201, and the control unit 202 analyzes and corrects the data acquired by the acquisition unit 201 to evaluate the real-time status of the generator and the power supply grid 206.
In addition, the control unit 202 includes, but is not limited to, a connection to the central control platform for receiving real-time instructions from an operator on the central control platform. The control unit 202 combines the collected data sent by the collecting unit 201 and the real-time command sent by the operator on the central control platform to generate at least a converter triggering command.
The generator module 203, including a three-phase synchronous alternator, generates ac power. The generator generally comprises a permanent magnet generator and an excitation generator, wherein a winding of the excitation generator is divided into a stator winding and an excitation winding, and the stator winding is connected with a three-phase alternating current input end of a converter; the field winding is connected to the dc output of the field unit 207. If the generator is a permanent magnet generator, the wind power system does not have to comprise an excitation unit 207. The permanent magnet synchronous generator consists of a fixed stator and a rotatable permanent magnet rotor. Due to the relative cutting action between the winding and the main magnetic field, a three-phase symmetrical alternating potential will be induced in the winding that varies periodically in magnitude and direction. And an alternating current power supply can be provided through the outgoing line.
And the three-level module unit group 204 is connected to the generator module 203 and the control unit 202, and is used for controlling the variable speed of the generator module 203 to output the first-level alternating current with fixed frequency after controllable rectification and inversion according to the trigger instruction sent by the control unit 202.
In an embodiment of the present invention, the wind power generation system comprises a total of 3 tri-level module unit groups 204, wherein each tri-level module unit group 204 comprises N tri-level module units, and thus the wind power generation system comprises 3 × N tri-level module units, and each tri-level module unit is connected to the multi-winding transformer 205. The details of the connecting lines of the tri-level module unit group 204 and the internal details of the tri-level module unit will be described in detail in fig. 3 and 7, which are not repeated herein.
And the multi-winding transformer 205 is connected with the three-level module unit group 204, and is used for converting the alternating current of the first level output by the three-level module unit group 204 into the alternating current of the second level and outputting the alternating current to the grid side of the power supply grid 206.
The multi-winding transformer should have 3 × N three-phase connectors for connecting N three-level module units. The multi-winding transformer is wound with a primary winding and a plurality of secondary windings on the iron core. The terminal voltage of each secondary winding is different when the number of turns of the secondary winding is different, so that the multi-winding transformer can supply power to several electric devices with different voltages.
As shown in fig. 2, in an embodiment of the present invention, since the acquisition unit 201 is adopted to acquire real-time data, grid-side voltage, and grid-side current on the synchronous generator and to send the acquired data to the control unit 202 in time, the present invention can know real-time states of the synchronous generator and the power supply grid in real time, and ensure normal operation of the synchronous generator and the power supply grid 206, and in addition, since the tri-level module unit group 204 is adopted instead of a single tri-level module unit, the present invention can meet the requirement of high voltage class.
Fig. 3 is a block diagram showing the details of the internal connections of the three-level module cell group in the converter shown in fig. 2. As shown in fig. 3, the synchronous power generation system 200 includes a collection unit 201, a control unit 202, a generator module 203, a three-level module unit 20411, a three-level module unit 20421, a three-level module unit 20431, and a plurality of three-level module units, a multi-winding transformer 205, a power supply grid 206, and an excitation unit 207. Fig. 3 highlights the connection details of the three-level block unit group 204.
Since fig. 3 is a detailed diagram based on fig. 2, fig. 3 is different from fig. 2 only in the three-level module unit group 204, and thus the description of the three-level module unit group 204 will be emphasized without introducing excessive description of other parts in this section.
Each three-level module unit group 204 includes N three-level module units, and since the wind power generation system of the present invention includes the 3-phase three-level module unit group 204, therefore, the wind power generation system of the invention comprises 3 × N three-level module units which are numbered 20411-, that is, the first ac input terminal of the three-level module unit 20411 is connected to the second ac input terminal of the three-level module unit 20412, the first ac input terminal of the three-level module unit 20412 is connected to the second ac input terminal of the three-level module unit 20413, and so on until the last three-level module unit 2041N.
In addition, the three-level module units included in the three-level module unit group 204 are connected in cascade, and the second ac input terminals of the first-level three-level module units of each phase are connected to each other, that is, the second ac input terminal of the three-level module unit 20411, the second ac input terminal of the three-level module unit 20421, and the second ac input terminal of the three-level module unit 20431 are connected together. In addition, the first ac input terminals of the last-stage three- level module units 2041N, 2042N, and 2043N are respectively connected to the phase a, the phase B, and the phase C of the synchronous generator 2031 for receiving the ac power generated by the synchronous generator. In addition, each three-level modular unit is connected to a multi-winding transformer 205.
Through the combination of the cascade connection and the parallel connection, the range of the voltage grade compatible with the converter is greatly expanded, and the grade of the mainstream voltage on the market can be met.
Fig. 4 shows an equivalent circuit diagram of d and q axes of an excited synchronous generator in the prior art.
In excitation synchronous generator control, in order to obtain control characteristics similar to a direct current motor, a coordinate system is established on a generator rotor, the coordinate system and the rotor rotate synchronously, and the direction of a rotor magnetic field is taken as a d axis (a direct axis) and the direction perpendicular to the rotor magnetic field is taken as a q axis (a quadrature axis).
An electrically excited synchronous machine (undamped winding) ignores magnetic field saturation, and a mathematical model under a synchronous rotation dq coordinate system can be expressed as:
voltage equation:
the flux linkage equation:
the torque equation:
Te＝1.5P[Ladif+(Ld-Lq)id]iq
wherein: p is a differential factor
ud，uqD, the terminal voltage of a q-axis motor; i.e. id，iq，ifD, q-axis stator current and excitation winding current; r, Ld，Lq，LadThe inductance is a stator resistance, a d-axis inductance, a q-axis inductance and a d-axis armature reaction inductance; phi is asd，φsq，φsThe amplitudes of the stator flux linkage of the d axis of the stator, the stator flux linkage of the q axis of the stator and the stator flux linkage are obtained; omegar，TeThe angular speed and electromagnetic torque of the motor.
The decoupling of the d axis and the q axis can be realized by converting the mathematical model of the generator into the coordinate system, so that good control characteristics are obtained. Therefore, the excitation synchronous generator has the advantages of strong overload capacity, high efficiency, adjustable power factor and the like.
Fig. 5 is a block diagram of a synchronous wind power generation system implemented by using a three-level module unit group and outputting a voltage of 6KV level according to an embodiment of the present invention, as shown in fig. 5, including a generator-side current sensor 2011, an excitation unit-side current sensor 2012, a control unit 202, a generator module 203, an excitation unit 207, three- level module units 20411, 20421, and 20431, a multi-winding transformer 205, and a power supply grid 206.
Wherein, the generator side current sensor 2011 is used for collecting the real-time data of the generator on the generator module 203, wherein the real-time data comprises real-time current data of the generator module 203, the exciting unit side current sensor 2012 is used for collecting the real-time data on the exciting unit 207, wherein, the real-time data includes real-time current data of the excitation unit 207, the synchronous generator side current sensor 2011 sends the acquired real-time current data of the generator on the generator module 203 to the control unit 202, the control unit 202 judges whether the generator on the generator module 203 is in a normal working state according to the real-time current data, in addition, the exciting unit side current sensor 2012 sends the acquired real-time current data of the generator on the generator module 203 to the control unit 202, and the control unit 202 determines whether the exciting unit 207 is in a normal working state according to the real-time current data.
The generator on the generator module 203 is used for outputting ac power to the three-level module unit group 204, and if the generator on the generator module 203 is a permanent magnet synchronous generator, the dashed frame portion in the figure, i.e., the excitation unit 207, can be simplified. The exciting unit 207 is connected to a first dc output terminal of the three-level module unit 20411. To provide field current to the generator on the generator module 203. The exciter unit is described in detail with reference to figure 8.
In an embodiment of the present invention, the wind power generation system includes 3 three-level module units in total, which are three- level module units 20411, 20421, and 20431, respectively, a second ac input terminal of the three-level module unit 20411, a second ac input terminal of the three-level module unit 20421, and a second ac input terminal of the three-level module unit 20431 are connected in parallel, and in addition, a first ac input terminal of the three-level module unit 20411, a first ac input terminal of the three-level module unit 20421, and a first ac input terminal of the three-level module unit 20431 are connected to the a phase, the B phase, and the C phase of the synchronous generator 2031, respectively. The first ac output terminal of the three-level module unit 20411, the first ac output terminal of the three-level module unit 20421, and the first ac output terminal of the three-level module unit 20431 are all connected to the multi-winding transformer 205. The multi-winding transformer 205 receives the ac power output by the three-level module unit group 204 and converts the ac power to the 6KV voltage required by the power grid to transmit to the power grid 206.
In the wind power generation system in an embodiment of the present invention, the tri-level module unit group 204 generates a high voltage to satisfy the requirement of the power grid 206 for a voltage of 6KV level through the cascade connection and the parallel connection between the tri-level module units.
Fig. 6 is a block diagram of a synchronous wind power generation system implemented by using a three-level module unit group and outputting 10 KV-level voltage, as shown in fig. 6, which includes a generator-side current sensor 2011, an excitation unit-side current sensor 2012, a control unit 202, a generator module 203, an excitation unit 207, three- level module units 20411, 20412, 20421, 20422, 20431, and 20432, a multi-winding transformer 205, and a power supply grid 206.
The difference between fig. 6 and fig. 5 is only in the three-level module unit group, and therefore other modules will not be described in detail in this section.
The wind power generation system 10KV voltage class scheme of an embodiment of the present invention includes 3-phase three-level module unit groups 204, wherein each three-level module unit group 204 includes 2 three-level modules.
The second ac input end of the three-level module unit 20411, the second ac input end of the three-level module unit 20421, and the second ac input end of the three-level module unit 20431 are connected in parallel, the first ac input end of the three-level module unit 20411 is connected to the second ac input end of the three-level module unit 20412, the first ac input end of the three-level module unit 20421 is connected to the second ac input end of the three-level module unit 20422, the first ac input end of the three-level module unit 20431 is connected to the second ac input end of the three-level module unit 20432, the first ac input end of the three-level module unit 20412, the first ac input end of the three-level module unit 20422, and the first ac input end of the three-level module unit 20432 are connected to the a phase, the B phase, and the C phase of the synchronous generator 2031, respectively, and the first ac output end of the three-level module unit 20411, The first ac output terminal of the three-level module unit 20412, the first ac output terminal of the three-level module unit 20421, the first ac output terminal of the three-level module unit 20422, the first ac output terminal of the three-level module unit 20431, and the first ac output terminal of the three-level module unit 20432 are all connected to the multi-winding transformer 205. The multi-winding transformer 205 receives the ac power output by the three-level module unit group 204 and converts the ac power to the 10KV voltage required by the power grid to transmit to the power grid 206.
In the wind power generation system in an embodiment of the present invention, the tri-level module unit group 204 generates a high voltage to satisfy the requirement of the 10KV class voltage required by the power grid 206 through the cascade connection and the parallel connection between the tri-level module units.
Fig. 7 is a circuit schematic of a diode-clamped three-level modular unit employed in one embodiment in accordance with the present invention. As shown in fig. 7, the three-phase bridge-arm voltage regulator comprises 5-phase bridge arms with the same structure, each phase of the bridge arm is provided with four power devices of controllable switches, two clamping diodes and four freewheeling diodes, the power devices of the four controllable switches are respectively connected with the four freewheeling diodes in anti-parallel, the power diodes are connected in series and are connected with the power devices of the two controllable switches in series, and two ends of a topological structure formed by parallel connection are respectively connected with the two power devices in series.
Fig. 8 is a schematic circuit diagram of an exciter unit employed in an embodiment in accordance with the present invention. As shown in fig. 8, the three-phase inverter includes a three-level phase module 801, a resonant module 802(Lf, Cf), a high-frequency transformer module 803(HTR), an uncontrolled rectifier module 804, an output LC module 805, and a chopper module 806(T5, R1).
The resonant module 802(Lf, Cf), the high-frequency transformer module 803(HTR), and the uncontrolled rectifier module 804 are combined together, and whether to use them is determined according to the design of the excitation voltage and the parameters of the dc voltage. If the excitation voltage is very different from the three-level block dc voltage, it can be selected, for example, to determine the excitation voltage 100V, and the three-level total dc voltage 4500V, then the HTR in the block is selected to be stepped down at high frequency to improve dynamic and steady-state effects. Energy may be discharged through the chopper paths (T5 and R1) when the dc voltage is too high.
FIGS. 9-10 are flowcharts illustrating operation of a wind power system according to an embodiment of the present invention. FIG. 9 is a flow chart of the operation of the wind turbine generator system when the excitation generator is selected; FIG. 10 is a flow chart of the operation of the wind turbine system with the permanent magnet generator.
As shown in fig. 9: first, step 901 is performed to determine whether the operator issues a start instruction. The step is executed immediately after the wind power generation system is powered on, and the purpose is to carry out the next step for judging whether the wind power generation system is in standby or started immediately after being powered on. If the operator does not send a start command, the system will perform step 902, if the operator sends a start command, the system will perform step 903;
in step 902, the wind power generation enters a standby state. If the operator does not send a starting instruction, the wind power generation system enters a standby state to wait for the starting instruction of the operator, which indicates that the operator does not need to start the wind power generation system;
in step 903, it is determined whether the wind power generation system has a fault. If the operator sends a starting instruction, the fact that the operator needs to start the wind power generation system is indicated, and the wind power generation system carries out fault detection so as to ensure that the wind power generation system can normally run;
next, in step 904, a fault command is returned to the central control platform. If the fault detection result shows that the wind power generation system has a fault, the step is switched to, the fault condition is reported to the central control platform, and a next step instruction of the central control platform is waited. If the fault detection result shows that the wind power generation system has no fault, the system executes step 905;
at this point, the wind power system has completed its early monitoring and the wind power system will proceed to step 906. Waiting for an operator to input the parameters of the wind power generation at this time and preparing for the wind power generation.
The system performs step 907 and the exciter unit starts to operate, and since the generator in the present system is an exciter generator, the exciter unit starts to operate in this step for supplying an exciting current.
The system executes a step 908, wherein a collecting unit collects real-time operation data on the synchronous generator and network side voltage and network side current on a power supply grid, and the step is early data collecting work after the wind power generation system starts to generate power and is used for monitoring the operation data of the system in real time to ensure the normal work of the system;
then the system executes step 909, the control unit sends a three-level trigger instruction through calculation according to the power instruction of the upper computer, and starts a three-level module unit group to control the magnitude of the stator current of the generator; the size of the exciting current is dynamically adjusted to rectify the alternating current output by the synchronous generator; then, step 9010 is executed, and the three-level module unit group outputs alternating current;
finally, step 9011 is executed, and the multi-winding transformer outputs the voltage required by the power supply grid.
As shown in fig. 10: first, step 1001 is performed to determine whether the operator issues a start command. The step is executed immediately after the wind power generation system is powered on, and the purpose is to carry out the next step for judging whether the wind power generation system is in standby or started immediately after being powered on. If the operator does not send a start command, the system will perform step 1002, if the operator sends a start command, the system will perform step 1003;
next, in step 1003, it is determined whether or not there is a failure in the wind turbine generator system. If the operator sends a starting instruction, the fact that the operator needs to start the wind power generation system is indicated, and the wind power generation system carries out fault detection so as to ensure that the wind power generation system can normally run;
in step 1004, a failure instruction is returned to the central control platform. If the fault detection result shows that the wind power generation system has a fault, the step is switched to, the fault condition is reported to the central control platform, and a next step instruction of the central control platform is waited. If the fault detection result shows that the wind power generation system has no fault, the system will execute step 1005;
at this point, the wind power generation system has completed its early monitoring and the wind power generation system will proceed to step 1006. Waiting for an operator to input the parameters of the wind power generation at this time and preparing for the wind power generation.
The system executes a step 1007, wherein a collecting unit collects real-time operation data on the synchronous generator and network side voltage and network side current on a power supply grid, and the step is early data collecting work after the wind power generation system starts to generate power and is used for monitoring the operation data of the system in real time to ensure the normal work of the system;
then the system executes step 1008, the control unit sends a three-level trigger instruction, and starts a three-level module unit group to rectify the alternating current output by the synchronous generator; then, in step 1009, the three-level module unit group outputs an alternating current;
finally, step 1010 is executed, and the multi-winding transformer outputs the voltage required by the power supply grid.
It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures, process steps, or materials disclosed herein but are extended to equivalents thereof as would be understood by those ordinarily skilled in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (9)
1. A converter for a synchronous machine wind power system, characterized in that it comprises:
the acquisition unit is connected to a three-phase synchronous generator and a power supply grid and is used for acquiring real-time operation data on the three-phase synchronous generator and grid-side voltage and grid-side current on the power supply grid;
the control unit is connected with the acquisition unit and used for receiving the real-time operation data of the three-phase synchronous generator, the network side voltage and the network side current sent by the acquisition unit and generating at least a converter trigger instruction according to the real-time operation data, the network side voltage and the network side current;
the three-level module unit group is connected to the three-phase synchronous generator, the control unit, the excitation winding and the multi-winding transformer, and is used for controlling and converting the changed alternating current of the three-phase synchronous generator according to a trigger instruction sent by the control unit, and outputting the alternating current with fixed frequency and a first level after rectification and inversion;
the three-level module unit group connected with each phase of the three-phase synchronous generator comprises at least one three-level module unit, each unit of the module unit group comprises a three-phase alternating current part and a single-phase alternating current part, the three-phase alternating current part is connected with a transformer, the single-phase alternating current part is connected with the synchronous motor after being cascaded, the single-phase alternating current part is connected to a three-phase stator winding of the generator after being cascaded, and for the electrically excited synchronous generator, one three-level power unit is also connected to an excitation unit, and the output of the three-level power unit is connected to an excitation winding of the generator;
the excitation unit comprises a three-level phase module, a resonance module, a high-frequency transformer module, an uncontrolled rectifier module, an output LC module and a chopping module which are sequentially connected, wherein the resonance module, the high-frequency transformer module and the uncontrolled rectifier module are combined together to decide whether to select or not according to the design of excitation voltage and the parameters of direct current voltage;
each three-level module unit comprises 5-phase bridge arms with the same structure, each phase of bridge arm is provided with four power devices of controllable switches, two clamping diodes and four freewheeling diodes, the power devices of the four controllable switches are respectively connected with the four freewheeling diodes in an anti-parallel mode, the clamping diodes are connected in series and are connected with the power devices of the two controllable switches in series in parallel, and two ends of a topological structure formed by the parallel connection are respectively connected with the two power devices in series;
and the multi-winding transformer is connected with the three-level module unit group and used for converting the alternating current of the first grade output by the three-level module unit group into the alternating current of the second grade and outputting the alternating current to the power supply network side.
2. The converter according to claim 1, wherein the three-level module cell groups between phases are connected as follows:
and second alternating current input ends of the three-level module units of each first stage are mutually connected.
3. The converter according to claim 2, wherein the three-level module units included in the three-level module unit group are cascade-connected as follows:
and the first alternating current input end of the three-level module unit at the previous stage is connected with the second alternating current input end of the three-level module unit at the next stage.
4. The converter according to claim 3, wherein the tri-level module cell group is connected to the multi-winding transformer in the following manner:
and the alternating current output end of each three-level module unit in each phase of three-level module unit group is connected to the multi-winding transformer.
5. The converter according to claim 4, wherein the three-level module cell group is connected to the three-phase synchronous generator by:
and the first alternating current input end of the last stage of the three-level module unit group of each phase is connected with the three-phase alternating current output end of the three-phase synchronous generator in a one-to-one correspondence manner.
6. The converter according to any of claims 1 to 5, wherein the control unit is communicatively connected to a central control platform for receiving control commands from an operator to determine whether to send a trigger command.
7. A synchronous wind power system, characterized in that the system comprises:
a three-phase synchronous generator for generating electricity;
the current transformer of any one of claims 1-6.
8. The synchronous wind power generation system of claim 7, wherein the three-phase synchronous generator is an electrically excited synchronous generator, wherein the excitation unit comprises:
the three-level module converts a first-level direct current output by a direct current output end of a first-level three-level module unit in the first-phase three-level module unit group into a second-level alternating current;
the resonant circuit module is used for generating resonance to transfer energy;
the high-frequency transformer module is used for converting the second-stage alternating current into third-stage alternating current;
the uncontrolled rectifying module is used for converting the third-stage alternating current into fourth-stage direct current;
the output LC module is used for filtering the output voltage, and the filtered voltage is used as an excitation voltage; and
and the chopping module is used for releasing energy through a chopping path when the excitation voltage is overhigh.
9. The system of claim 8, wherein the control unit sends a trigger instruction to the energizing unit to trigger the energizing unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710567986.4A CN109256794B (en) | 2017-07-12 | 2017-07-12 | Converter for synchronous wind power generation system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710567986.4A CN109256794B (en) | 2017-07-12 | 2017-07-12 | Converter for synchronous wind power generation system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109256794A CN109256794A (en) | 2019-01-22 |
| CN109256794B true CN109256794B (en) | 2021-05-07 |
Family
ID=65051689
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710567986.4A Active CN109256794B (en) | 2017-07-12 | 2017-07-12 | Converter for synchronous wind power generation system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109256794B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112737469B (en) * | 2020-12-31 | 2024-05-17 | 江苏国传电气有限公司 | Variable frequency driving device and control method for electric excitation synchronous motor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103762615A (en) * | 2014-01-02 | 2014-04-30 | 兰州交通大学 | Megawatt grid connection converter |
| CN106787814A (en) * | 2017-03-29 | 2017-05-31 | 哈尔滨理工大学 | Nine level current transformers of magneto alternator |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2633453B2 (en) * | 1976-07-24 | 1981-02-19 | Te Ka De Felten & Guilleaume Fernmeldeanlagen Gmbh, 8500 Nuernberg | Carrier frequency system without switching filter |
| CN102281006A (en) * | 2011-03-31 | 2011-12-14 | 东北大学 | Novel three-level soft switching converter |
| CN102386633A (en) * | 2011-11-07 | 2012-03-21 | 荣信电力电子股份有限公司 | Megawatt direct-drive alternating current-direct current-alternating current wind power generating system with squirrel-cage asynchronous generator |
-
2017
- 2017-07-12 CN CN201710567986.4A patent/CN109256794B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103762615A (en) * | 2014-01-02 | 2014-04-30 | 兰州交通大学 | Megawatt grid connection converter |
| CN106787814A (en) * | 2017-03-29 | 2017-05-31 | 哈尔滨理工大学 | Nine level current transformers of magneto alternator |
Non-Patent Citations (2)
| Title |
|---|
| Simulation study of transverse flux linear switched reluctance drive;Ge Baoming et al;《2005 International Conference on Electrical Machines and Systems》;20060116;608-603 * |
| 兆瓦级永磁直驱式风力发电系统中背靠背变流器系统的设计;肖飞等;《船电技术》;20100131;第30卷(第1期);1-6 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109256794A (en) | 2019-01-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Rajaei et al. | Vienna-rectifier-based direct torque control of PMSG for wind energy application | |
| Chen et al. | Analysis of squirrel-cage induction generator with Vienna rectifier for wind energy conversion system | |
| CN106160606B (en) | Wind generator system and its control method | |
| CN103280838B (en) | A kind of wind power generation high voltage direct current grid-connected system and control method thereof based on opening winding construction | |
| CN101345423B (en) | 5-power level H-bridge cascade connection back-to-back current transformer used for wind power generation system | |
| CN104539206B (en) | Marine large-scale straight drive switching magnetic-resistance wind-driven generator power converter system | |
| Lee et al. | Wind power collection and transmission with series connected current source converters | |
| CN113258843A (en) | Direct-drive wind turbine generator motor rotating speed control method, control system and grid-connected system | |
| CN106356889A (en) | Permanent magnet wind power generator set | |
| CN112217238B (en) | Brushless doubly-fed generator system and control method thereof | |
| Iov et al. | Power electronics and control for wind power systems | |
| CN109256794B (en) | Converter for synchronous wind power generation system | |
| CN105763114A (en) | Control method of duplex-winding asynchronous-motor alternating current and direct current starting power generation system | |
| CN104682444A (en) | Control method of permanent magnetic direct drive type wind power system converter of power grid | |
| CN105763116B (en) | A kind of topological structure of double-winding asynchronous alternating current-direct current starting-generating system | |
| Keyuan et al. | Investigation of a matrix converter-excited brushless doubly-fed machine wind-power generation system | |
| CN104378034B (en) | The operation control system of brushless ac compound rectifier excitation brshless DC motor | |
| CN204334399U (en) | The operation control system of brushless ac compound rectifier excitation brshless DC motor | |
| Hwang et al. | Vector control of multiple-module transverse flux PM generator for large-scale direct-drive wind turbines | |
| Dongling et al. | Coordination control for offshore wind power sending through hybrid HVDC | |
| Bayhan et al. | Active and reactive power control of grid connected permanent magnet synchronous generator in wind power conversion system | |
| Garces et al. | Power collection array for improved wave farm output based on reduced matrix converters | |
| CN112671014A (en) | Flywheel energy storage variable speed power generation system | |
| CN202076803U (en) | Wind power generating equipment | |
| Xing et al. | New adaptive control strategies for open-end winding permanent magnet synchronous generator (OEW-PMSG) for wind power generation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |