CN106602611B - Wind power system based on single-quadrant converter flux weakening control and operation method thereof - Google Patents
Wind power system based on single-quadrant converter flux weakening control and operation method thereof Download PDFInfo
- Publication number
- CN106602611B CN106602611B CN201710091005.3A CN201710091005A CN106602611B CN 106602611 B CN106602611 B CN 106602611B CN 201710091005 A CN201710091005 A CN 201710091005A CN 106602611 B CN106602611 B CN 106602611B
- Authority
- CN
- China
- Prior art keywords
- converter
- wind
- quadrant
- direct
- 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
- 230000003313 weakening effect Effects 0.000 title claims abstract description 36
- 230000004907 flux Effects 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims description 24
- 238000004804 winding Methods 0.000 claims abstract description 79
- 230000002829 reductive effect Effects 0.000 claims abstract description 36
- 239000003990 capacitor Substances 0.000 claims abstract description 31
- 230000005284 excitation Effects 0.000 claims description 49
- 238000004146 energy storage Methods 0.000 claims description 21
- 230000001360 synchronised effect Effects 0.000 claims description 21
- 230000008569 process Effects 0.000 claims description 10
- 238000005259 measurement Methods 0.000 claims description 3
- 238000010248 power generation Methods 0.000 claims description 3
- 230000002441 reversible effect Effects 0.000 abstract description 12
- 230000008859 change Effects 0.000 abstract description 6
- 230000004044 response Effects 0.000 abstract description 3
- 230000007423 decrease Effects 0.000 description 10
- 230000000630 rising effect Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Images
Classifications
-
- H02J3/386—
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
-
- 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 wind power system based on single-quadrant converter flux weakening control provided by the embodiment of the invention provides unipolar armature voltage and armature current to a rotor armature winding of a direct current motor through a single-quadrant driving converter, provides unipolar exciting voltage and exciting current to a stator exciting winding of the direct current motor through an exciting converter, and is connected between a direct current bus capacitor and a power frequency power grid through a diode rectifier, so that a bridge type reversible PWM converter is replaced by the single-quadrant driving converter and the exciting converter, a three-phase PWM rectifier is replaced by the diode rectifier, the number of power switching tubes and switching loss are greatly reduced, meanwhile, the power fluctuation caused by the rapid response wind speed change of a wind driven generator to improve the wind energy utilization rate is compensated, and the technical problems that the three-phase PWM rectifier and the bridge type reversible PWM converter cause overhigh system cost and switching loss, the risk of damage caused by direct short circuit and the contradiction between the wind energy utilization rate and the power fluctuation are solved.
Description
Technical Field
The invention relates to the field of new energy power generation, in particular to a wind power system based on single-quadrant converter field weakening control and an operation method thereof.
Background
The variable frequency transformer is novel power grid interconnection equipment, and the equipment has unique advantages in solving a plurality of problems faced by wind power grid connection. On the one hand, the variable frequency transformer can be used for carrying out power grid friendly transformation on the constant-speed wind turbine generator set, so that the variable frequency transformer meets the requirements of a power grid on smoothness of output power of the wind turbine generator set, low voltage ride through capability and reactive support provision during power grid voltage drop. On the other hand, the variable frequency transformer is used for replacing a power electronic converter in a traditional wind power system, so that the capacity and cost of the power electronic device are greatly reduced, and the overload capacity of the power electronic device is obviously enhanced. In view of its unique advantages, a variable frequency transformer will play an increasingly important role in the wind grid connection field.
The current variable frequency transformer applied to wind power generation must be capable of rotating forward and backward and must be capable of providing forward and backward torque, so that the direct current motor must be driven by a converter capable of bidirectionally transmitting electric energy. Typically, as shown in fig. 1, the converter is comprised of a three-phase PWM rectifier that requires six power switching tubes and six freewheeling diodes, and a bridge type reversible PWM converter that requires four power switching tubes and four freewheeling diodes. Two adverse effects are generated, namely excessive system cost and switching loss caused by excessive power devices, and the risk of damage to the upper and lower switching tubes of the same bridge arm due to direct short circuit exists.
In addition, the existing wind power system based on the variable frequency transformer and comprising the three-phase PWM rectifier and the bridge type reversible PWM converter only utilizes the rotary energy storage of the wind turbine generator set to reduce the fluctuation of output power when the wind speed fluctuates, but does not utilize the rotary energy storage of the variable frequency transformer to reduce the fluctuation of power when the rotating speed of the wind turbine rapidly follows the change of the wind speed in the process of capturing the maximum wind energy. The disadvantage of this mode of operation is that: during the period that the rotating speed of the wind turbine rises rapidly along with the wind speed, a large amount of electric energy is required to be converted into the rotating kinetic energy of the wind turbine, the output power of the wind turbine can be temporarily reduced, and after the wind turbine operates at a new steady-state rotating speed, the output power of the wind turbine can rise rapidly; conversely, during the period that the rotating speed of the wind turbine rapidly decreases along with the wind speed, a large amount of rotating kinetic energy of the wind turbine is required to be converted into electric energy, the output power of the wind turbine temporarily increases, and after the wind turbine operates at a new steady-state rotating speed, the output power of the wind turbine rapidly decreases. Therefore, the dynamic response speed of the existing wind turbine generator system must be designed in a compromise between improving the wind energy utilization rate and reducing the power fluctuation.
Therefore, the contradiction between the three-phase PWM rectifier and the bridge type reversible PWM converter, which causes excessive system cost and switching loss, the risk of damage due to the through short circuit, the wind energy utilization rate and the power fluctuation, is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
The embodiment of the invention provides a wind power system based on single-quadrant converter field weakening control and an operation method thereof, which are used for solving the technical problems that the three-phase PWM rectifier and the bridge type reversible PWM converter cause excessive system cost and switching loss, risk of damage caused by direct short circuit exists, and contradiction between wind energy utilization rate and power fluctuation exists.
The embodiment of the invention provides a wind power system based on single-quadrant converter flux weakening control, which comprises: the variable frequency transformer comprises a doubly-fed motor, a direct-current motor, a single-quadrant driving converter, an excitation converter, a direct-current bus capacitor and a diode rectifier;
the rotor winding of the doubly-fed motor is connected with a wind generating set, the stator winding of the doubly-fed motor is connected with the power frequency power grid, and the doubly-fed motor is coaxially and mechanically connected with the direct-current motor;
one end of the single-quadrant driving converter is connected with a rotor armature winding of the direct current motor, and the other end of the single-quadrant driving converter is connected with the direct current bus capacitor;
one end of the excitation converter is connected with a stator excitation winding of the direct current motor, and the other end of the excitation converter is connected with the direct current bus capacitor;
the alternating current input end of the diode rectifier is connected with the power frequency power grid through the step-down transformer, and the direct current output end of the diode rectifier is connected with the direct current bus capacitor;
the single-quadrant driving converter is used for providing single-polarity armature voltage and armature current to a rotor armature winding of the direct-current motor, and the exciting converter is used for providing single-polarity exciting voltage and exciting current to a stator exciting winding of the direct-current motor.
Preferably, the single-quadrant drive converter comprises a first power switch tube and a first freewheel diode;
the emitter of the first power switch tube is connected with the cathode of the first freewheel diode;
the collector of the first power switch tube and the anode of the first freewheeling diode are respectively connected with the anode and the cathode of the direct-current bus capacitor;
and the cathode and the anode of the first freewheeling diode are respectively connected with the anode and the cathode of the armature winding of the rotor of the direct current motor.
Preferably, the excitation converter comprises a second power switch tube and a second freewheel diode;
the emitter of the second power switch tube is connected with the cathode of the second freewheel diode;
the collector electrode of the second power switch tube and the anode of the second freewheeling diode are respectively connected with the anode and the cathode of the direct-current bus capacitor;
and the cathode and the anode of the second follow current diode are respectively connected with the anode and the cathode of the stator exciting winding of the direct current motor.
Preferably, the diode rectifier comprises six rectifier diodes;
the six rectifier diodes are connected in parallel with the direct current bus capacitor after being connected in series in the same direction;
and three-phase wiring of the step-down transformer is respectively connected with the connecting parts of the rectifier diodes which are connected in series.
Preferably, the wind generating set comprises a wind turbine, a gear box and a synchronous generator;
the wind turbine is mechanically connected with the synchronous generator through the gear box;
the stator winding of the synchronous generator is connected with the rotor winding of the doubly-fed motor.
Preferably, the single-quadrant driving converter adopts a double closed-loop control algorithm;
the proportional integral regulator of the rotating speed outer ring obtains a rotor armature winding current given value of the direct current motor according to the difference value between the rotating speed given value of the variable frequency transformer and the corresponding measured value, the upper limit of the rotor armature winding current given value is set to be the rated current of the single-quadrant driving converter, and the lower limit of the rotor armature winding current given value is set to be zero;
and the proportional-integral regulator of the current inner loop obtains the duty ratio of the single-quadrant driving converter according to the difference value between the given value of the current of the armature winding of the rotor of the direct-current motor and the corresponding measured value.
Preferably, the rotating speed given value of the variable frequency transformer is calculated specifically according to a real-time measured wind speed and a maximum wind energy capturing control algorithm of the wind turbine.
Preferably, the excitation converter is controlled by an excitation current closed-loop control algorithm;
the proportional-integral regulator of the excitation converter calculates the duty ratio of the excitation converter according to the deviation between the given value of the stator excitation winding current of the direct-current motor and the corresponding measured value;
the exciting winding current given value is calculated specifically according to the real-time measurement rotating speed of the wind generating set.
Preferably, the wind generating set connected with the rotor winding of the doubly-fed motor is one or more than one group.
The wind power system operation method based on the single-quadrant converter flux weakening control provided by the embodiment of the invention is based on the wind power system operation based on the single-quadrant converter flux weakening control and comprises the following steps:
when the wind speed rises, the single-quadrant driving converter and the exciting converter of the variable frequency transformer control the rotation speed of the direct current motor to drop, so that the rotation speed of the wind generating set rises, and simultaneously the rotation energy storage of the doubly-fed motor and the direct current motor is released to compensate the rotation energy storage of the wind generating set;
when the wind generating set operates at the rated rotation speed, the single-quadrant driving converter and the exciting converter of the variable-frequency transformer control the rotation speed of the direct-current motor to be zero;
when the wind speed is reduced, the single-quadrant driving converter and the exciting converter of the variable-frequency transformer control the rotation speed of the direct-current motor to be increased, so that the rotation speed of the wind generating set is reduced, and meanwhile, the rotation energy storage of the wind generating set is absorbed to the rotation energy storage of the doubly-fed motor and the direct-current motor; in the process that the rotating speed of the wind generating set is reduced along with the wind speed, if the control voltage required by the rotor armature winding of the direct current motor exceeds the safety voltage of the first power switch tube and the first freewheel diode in the single-quadrant drive converter, the exciting winding current given value of the exciting converter is reduced, and the maximum wind energy capture of the wind generating set in a low wind speed section is realized.
From the above technical solutions, the embodiment of the present invention has the following advantages:
according to the wind power system based on single-quadrant converter flux weakening control, provided by the embodiment of the invention, the single-polarity armature voltage and armature current are provided for the rotor armature winding of the direct-current motor through the single-quadrant driving converter, the single-polarity exciting voltage and exciting current are provided for the stator exciting winding of the direct-current motor through the exciting converter, and the single-polarity exciting voltage and exciting current are connected between a direct-current bus capacitor and a power frequency power grid through the diode rectifier, so that the bridge type reversible PWM converter is replaced by the single-quadrant driving converter and the exciting converter, the three-phase PWM rectifier is replaced by the diode rectifier, the circuit of the variable-frequency transformer is simplified, the number of power switching tubes and switching loss are greatly reduced, and better economical efficiency is achieved; the damage of the power switch tube caused by the straight-through short circuit of the bridge arm can be completely avoided, and the reliability is better; meanwhile, when the wind power system based on the single-quadrant converter flux weakening control operates, the rotational kinetic energy absorbed (released) by the rising (falling) of the rotating speed of the wind generating set can be partially compensated by the rotational kinetic energy released (absorbed) by the falling (rising) of the rotating speed of the variable frequency transformer, so that the fluctuation of output power in the maximum wind energy capturing process can be reduced.
Therefore, the embodiment of the invention solves the technical problems of overhigh system cost and switching loss caused by the three-phase PWM rectifier and the bridge type reversible PWM converter, risk of damage caused by direct short circuit, and contradiction between wind energy utilization rate and power fluctuation.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic diagram illustrating a variable speed wind power system based on a variable frequency transformer in accordance with an embodiment of the present invention;
FIG. 2 is a schematic diagram of an embodiment of a wind power system based on single-quadrant converter flux weakening control according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of another embodiment of a wind power system based on single-quadrant converter flux weakening control according to an embodiment of the present invention;
FIG. 4 is a flowchart of an embodiment of a method for operating a wind power system based on single-quadrant converter flux weakening control according to an embodiment of the present invention;
wherein, the reference numerals are as follows:
1. a wind turbine; 2. a gear box; 3. a synchronous generator; 4. a variable frequency transformer; 5. a power frequency grid; 6. a step-down transformer; 7. a doubly-fed motor; 8. a DC motor; 9. a single-quadrant drive inverter; 10. an excitation converter; 11. a direct current bus capacitor; 12. diode rectifiers.
Detailed Description
The embodiment of the invention provides a wind power system based on single-quadrant converter field weakening control and an operation method thereof, which are used for solving the technical problems that the three-phase PWM rectifier and the bridge type reversible PWM converter cause excessive system cost and switching loss, risk of damage caused by direct short circuit exists, and contradiction between wind energy utilization rate and power fluctuation exists.
In order to make the objects, features and advantages of the present invention more comprehensible, the technical solutions in the embodiments of the present invention are described in detail below with reference to the accompanying drawings, and it is apparent that the embodiments described below are only some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 2, an embodiment of a wind power system based on field weakening control of a single-quadrant converter according to an embodiment of the present invention includes: the variable frequency transformer 4 comprises a doubly-fed motor 7, a direct-current motor 8, a single-quadrant drive converter 9, an excitation converter 10, a direct-current bus capacitor 11 and a diode rectifier 12;
the rotor winding of the doubly-fed motor 7 is connected with a wind generating set, the stator winding of the doubly-fed motor 7 is connected with a power frequency power grid 5, and the doubly-fed motor 7 is coaxially and mechanically connected with a direct-current motor 8;
one end of the single-quadrant driving converter 9 is connected with a rotor armature winding of the direct current motor 8, and the other end of the single-quadrant driving converter 9 is connected with a direct current bus capacitor 11;
one end of the excitation converter 10 is connected with a stator excitation winding of the direct current motor 8, and the other end of the excitation converter 10 is connected with a direct current bus capacitor 11;
the alternating current input end of the diode rectifier 12 is connected with the power frequency power grid 5 through the step-down transformer 6, and the direct current output end of the diode rectifier 12 is connected with the direct current bus capacitor 11;
wherein the single-quadrant drive inverter 9 is used for providing a single-polarity armature voltage and armature current to the rotor armature windings of the direct current motor 8, and the excitation inverter 10 is used for providing a single-polarity excitation voltage and excitation current to the stator excitation windings of the direct current motor 8.
The wind generating set comprises a wind turbine 1, a gear box 2 and a synchronous generator 3;
the wind turbine 1 is mechanically connected with the synchronous generator 3 through a gear box 2;
the stator windings of the synchronous generator 3 are connected to the rotor windings of the doubly-fed machine 7.
According to the wind power system based on single-quadrant converter flux weakening control, provided by the embodiment of the invention, single-polarity armature voltage and armature current are provided for a rotor armature winding of a direct-current motor 8 through a single-quadrant driving converter 9, single-polarity exciting voltage and exciting current are provided for a stator exciting winding of the direct-current motor 8 through an exciting converter 10, and the single-polarity exciting voltage and exciting current are connected between a direct-current bus capacitor 11 and a power frequency power grid 5 through a diode rectifier 12, so that a bridge type reversible PWM converter is replaced by the single-quadrant driving converter 9 and the exciting converter 10, and a three-phase PWM rectifier is replaced by the diode rectifier 12, so that a circuit of a variable-frequency transformer 4 is simplified, the number of power switching tubes and switching losses are greatly reduced, and better economy is achieved; the damage of the power switch tube caused by the straight-through short circuit of the bridge arm can be completely avoided, and the reliability is better; meanwhile, when the wind power system based on the single-quadrant converter flux weakening control operates, the rotational kinetic energy absorbed (released) by the rising (falling) of the rotating speed of the wind generating set can be partially compensated by the rotational kinetic energy released (absorbed) by the falling (rising) of the rotating speed of the variable frequency transformer 4, so that the fluctuation of output power in the maximum wind energy capturing process can be reduced.
Therefore, the embodiment of the invention solves the technical problems of overhigh system cost and switching loss caused by the three-phase PWM rectifier and the bridge type reversible PWM converter, risk of damage caused by direct short circuit, and contradiction between wind energy utilization rate and power fluctuation.
The foregoing describes one embodiment of a wind power system based on single-quadrant converter flux weakening control according to the embodiments of the present invention in detail, and the following describes another embodiment of a wind power system based on single-quadrant converter flux weakening control according to the embodiments of the present invention in detail.
Referring to fig. 3, another embodiment of a wind power system based on field weakening control of a single-quadrant converter according to an embodiment of the present invention includes: the variable frequency transformer 4 comprises a doubly-fed motor 7, a direct-current motor 8, a single-quadrant drive converter 9, an excitation converter 10, a direct-current bus capacitor 11 and a diode rectifier 12;
the rotor winding of the doubly-fed motor 7 is connected with a wind generating set, the stator winding of the doubly-fed motor 7 is connected with a power frequency power grid 5, and the doubly-fed motor 7 is coaxially and mechanically connected with a direct-current motor 8;
one end of the single-quadrant driving converter 9 is connected with a rotor armature winding of the direct current motor 8, and the other end of the single-quadrant driving converter 9 is connected with a direct current bus capacitor 11;
one end of the excitation converter 10 is connected with a stator excitation winding of the direct current motor 8, and the other end of the excitation converter 10 is connected with a direct current bus capacitor 11;
the alternating current input end of the diode rectifier 12 is connected with the power frequency power grid 5 through the step-down transformer 6, and the direct current output end of the diode rectifier 12 is connected with the direct current bus capacitor 11;
wherein the single-quadrant drive inverter 9 is used for providing a single-polarity armature voltage and armature current to the rotor armature windings of the direct current motor 8, and the excitation inverter 10 is used for providing a single-polarity excitation voltage and excitation current to the stator excitation windings of the direct current motor 8.
The single-quadrant drive converter 9 comprises a first power switch tube and a first freewheel diode;
an emitter of the first power switch tube is connected with a cathode of the first freewheel diode;
the collector of the first power switch tube and the anode of the first freewheeling diode are respectively connected with the anode and the cathode of the direct current bus capacitor 11;
the cathode and anode of the first freewheel diode are connected to the anode and cathode of the rotor armature winding of the direct current motor 8, respectively.
The excitation inverter 10 includes a second power switching tube and a second freewheel diode;
an emitter of the second power switch tube is connected with a cathode of the second freewheel diode;
the collector of the second power switch tube and the anode of the second freewheeling diode are respectively connected with the anode and the cathode of the direct current bus capacitor 11;
the cathode and anode of the second freewheeling diode are connected to the stator field winding of the DC motor 8.
The diode rectifier 12 includes six rectifying diodes;
six rectifier diodes are connected in parallel with the direct current bus capacitor 11 after being connected in series in the same direction;
the three-phase connection of the step-down transformer 6 is respectively connected with the connection parts of the rectifier diodes which are connected in series.
The wind generating set comprises a wind turbine 1, a gear box 2 and a synchronous generator 3;
the wind turbine 1 is mechanically connected with the synchronous generator 3 through a gear box 2;
the stator windings of the synchronous generator 3 are connected to the rotor windings of the doubly-fed machine 7.
The single-quadrant driving converter 9 adopts a double closed-loop control algorithm;
the proportional integral regulator of the outer ring of the rotational speed obtains the rotor armature winding current set point of the direct-current motor 8 according to the difference value of the rotational speed set point of the variable frequency transformer 4 and corresponding measured value, the upper limit of the rotor armature winding current set point is set as the rated current of the single-quadrant driving converter 9, the lower limit of the rotor armature winding current set point is set as zero;
the proportional integral regulator of the current inner loop obtains the duty ratio of the single-quadrant driving converter 9 according to the difference value between the given value of the current of the armature winding of the rotor of the direct-current motor 8 and the corresponding measured value;
the given value of the exciting winding current is calculated specifically according to the real-time measured rotational speed of the variable frequency transformer 4, when the rotational speed of the variable frequency transformer is zero, the given value of the exciting winding current is equal to the rated value, and the given value of the exciting winding current is reduced along with the rise of the rotational speed of the variable frequency transformer 4.
The rotational speed of the variable frequency transformer 4 generally refers to the rotational speed of its internal motors (doubly-fed motor 7 and direct-current motor 8).
The rotation speed given value of the variable frequency transformer 4 is calculated specifically according to the real-time measured wind speed and the maximum wind energy capturing control algorithm of the wind turbine 1.
The excitation converter 10 is controlled by an excitation current closed-loop control algorithm;
the proportional-integral regulator of the excitation converter 10 calculates the duty ratio of the excitation converter 10 according to the deviation between the given value of the stator excitation winding current of the direct-current motor 8 and the corresponding measured value;
the exciting winding current set value is calculated specifically according to the real-time measurement rotating speed of the wind generating set.
The wind generating set connected with the rotor winding of the doubly-fed motor 7 is one group or more than one group.
The invention relates to a wind power system based on single-quadrant converter flux weakening control, which comprises a wind turbine 1, a gear box 2, an induction synchronous generator 3, a variable frequency transformer 4, a step-down transformer 6 and a power frequency power grid 5, wherein the variable frequency transformer 4 comprises a doubly-fed motor 7, a direct-current motor 8, a single-quadrant driving converter 9, an excitation converter 10, a direct-current bus capacitor 11 and a diode rectifier 12. In this system, the variable frequency transformer 4 only needs to achieve unidirectional rotation under unidirectional torque, so the driving converter only needs to adopt a single-quadrant converter consisting of one power switch tube and one freewheel diode. Compared with the prior variable frequency transformer 4, the number of the power switching tubes and the switching loss of the driving converter adopted by the invention are obviously reduced, and the damage of the power switching tubes caused by the straight-through short circuit of bridge arms can be completely avoided. When the rotating speed of the variable frequency transformer 4 is higher, the field-weakening control is adopted in the excitation converter 10, so that the maximum wind energy capture of the wind turbine 1 in a larger wind speed range can be ensured, and meanwhile, the withstand voltage level of a power switch tube and a flywheel diode in the single-quadrant driving converter 9 can be reduced. The rotational speed of the wind turbine 1, the gearbox 2 and the synchronous generator 3 is fast responsive to wind speed changes, and the induced power fluctuations can be partially compensated by the rotational energy storage of the variable frequency transformer 4. The invention can obviously reduce the cost of the driving converter in the variable frequency transformer, improve the reliability of the driving converter and reduce the fluctuation of the output power in the maximum wind energy capturing process. The invention can control a single wind turbine and can also control a plurality of wind turbines.
When the rotating speed of the variable frequency transformer 4 is zero, the wind turbine 1 operates at the rated rotating speed, when the rotating speed of the variable frequency transformer 4 is positively increased, the rotating speed of the wind turbine 1 is reduced, and when the variable frequency transformer 4 operates at the positive highest rotating speed, the wind turbine 1 operates at the lowest rotating speed; the armature winding of the rotor of the DC motor 8 in the variable frequency transformer 4 adopts a single-quadrant driving converter 9 consisting of a power switch tube and a freewheel diode to provide unipolar armature voltage and armature current; the stator exciting winding of the direct current motor 8 in the variable frequency transformer 4 adopts an exciting converter 10 consisting of a power switch tube and a freewheel diode to provide unipolar exciting voltage and exciting current; the excitation inverter 10 outputs a rated excitation current when the wind turbine 1 is operated at a rated rotational speed, and the excitation current output by the excitation inverter 10 decreases when the rotational speed of the wind turbine 1 decreases.
The rotational energy stored by the rapid rising of the rotational speed of the wind turbine 1, the gear box 2 and the synchronous generator 3 can be partially compensated by the rotational energy stored released by the falling of the rotational speed of the variable frequency transformer 4; the rotational energy stored by the wind turbine 1, the gear box 2 and the synchronous generator 3 which are released by the rapid decrease of the rotation speed can be partially compensated by the rotational energy stored by the absorption of the increase of the rotation speed of the variable frequency transformer 4; when the rotating speed of the wind turbine 1 rapidly responds to the change of wind speed so as to achieve maximum wind energy capture, the fluctuation of the output power of the wind power system is reduced.
The single-quadrant driving converter 9 with a very simple structure is used in the driver of the direct current motor 8 of the variable frequency transformer 4 of the variable speed wind power system, the voltage withstand level of a switching device in the single-quadrant driving converter 9 is effectively reduced by combining with weak magnetic control, the stable operation of the variable frequency transformer 4 is ensured, the maximum wind energy capture of the wind turbine 1 can be realized in a larger wind speed range, and the output power fluctuation given in the maximum wind energy capture process is reduced.
The rotor winding of the doubly-fed motor 7 can be connected with one wind power generator independently or with a plurality of wind power generators with close wind conditions.
It should be noted that the embodiment of the invention has the following advantages and beneficial effects:
1. in the variable speed wind power system, the driver of the direct current motor 8 required by the variable frequency transformer 4 adopts a single-quadrant driving converter 9 consisting of one power switch tube and one freewheel diode, and compared with the bridge type reversible PWM converter mainly adopted at present and comprising four power switch tubes and four freewheel diodes, the driver has the following advantages: the number of the power switch tubes and the switching loss are greatly reduced, so that the power switch tube has better economy; the damage of the power switch tube caused by the bridge arm through short circuit can be completely avoided, and the reliability is better.
2. In the variable speed wind power system, the rectifier between the direct current bus capacitor 11 and the power frequency power grid 5 adopts a rectifier composed of six diodes, and compared with the current PWM rectifier mainly adopted at present and comprising six power switching tubes and six freewheel diodes, the rectifier has the following advantages: the number of the power switch tubes and the switching loss are greatly reduced, and the power switch tube has better economy.
3. In a variable speed wind power system, the rotational speed of the wind turbine 1 must quickly follow the wind speed changes in order to better achieve maximum wind energy capture. When the wind speed rises, the rotating speed of the wind turbine 1 rises rapidly, and a large amount of electric energy needs to be converted into the rotating kinetic energy of the wind turbine 1, the gear box 2 and the synchronous generator 3; when the wind speed is reduced, the rotating speed of the wind turbine 1 is rapidly reduced, and a large amount of rotational kinetic energy is required to be converted into electric energy. The rotational kinetic energy absorbed (released) by the rising (falling) of the rotational speed of the wind turbine 1, the gearbox 2 and the synchronous generator 3 can be partially compensated by the rotational kinetic energy released (absorbed) by the falling (rising) of the rotational speed of the variable frequency transformer 4, and thus the output power fluctuation during the maximum wind energy capturing process can be reduced.
Therefore, the invention helps to promote the practical application of the variable-speed wind power system based on the variable-frequency transformer.
The foregoing describes another embodiment of a wind power system based on single-quadrant converter flux weakening control provided by the embodiment of the present invention in detail, and the following describes one embodiment of a wind power system operation method based on single-quadrant converter flux weakening control provided by the embodiment of the present invention in detail.
Referring to fig. 4, an embodiment of a method for operating a wind power system based on single-quadrant converter flux weakening control according to the present invention includes:
101: when the wind speed rises, the single-quadrant driving converter and the exciting converter of the variable frequency transformer control the rotation speed of the direct current motor to drop, so that the rotation speed of the wind generating set rises, and simultaneously the rotation energy storage of the doubly-fed motor and the direct current motor is released to compensate the rotation energy storage of the wind generating set;
102: when the wind generating set operates at the rated rotation speed, the single-quadrant driving converter and the exciting converter of the variable-frequency transformer control the rotation speed of the direct-current motor to be zero;
103: when the wind speed is reduced, the single-quadrant driving converter and the exciting converter of the variable-frequency transformer control the rotation speed of the direct-current motor to be increased, so that the rotation speed of the wind generating set is reduced, and meanwhile, the rotation energy storage of the wind generating set is absorbed to the rotation energy storage of the doubly-fed motor and the direct-current motor; in the process that the rotating speed of the wind generating set is reduced along with the wind speed, if the control voltage required by the rotor armature winding of the direct current motor exceeds the safety voltage of the first power switch tube and the first freewheel diode in the single-quadrant drive converter, the exciting winding current given value of the exciting converter is reduced, and the maximum wind energy capture of the wind generating set in a low wind speed section is realized.
It should be noted that 101, 102, 103 are not performed in steps, but are operated correspondingly according to the current wind speed, and when the wind speed is in different stages, the single-quadrant driving converter and the exciting converter of the variable frequency transformer control the rotation speed of the direct current motor to change correspondingly according to a preset operation program.
In the existing variable-speed wind power system based on the variable-frequency transformer, only the rotational energy storage of a wind turbine generator is utilized, the fluctuation of output power is reduced when the wind speed fluctuates, but the rotational energy storage of the variable-frequency transformer is not utilized in the maximum wind energy capturing process, and the power fluctuation is reduced when the rotating speed of the wind turbine rapidly follows the change of the wind speed. The disadvantage of this mode of operation is that: during the period that the rotating speed of the wind turbine rises rapidly along with the wind speed, a large amount of electric energy is required to be converted into the rotating kinetic energy of the wind turbine, the output power of the wind turbine can be temporarily reduced, and after the wind turbine operates at a new steady-state rotating speed, the output power of the wind turbine can rise rapidly; conversely, during the period that the rotating speed of the wind turbine rapidly decreases along with the wind speed, a large amount of rotating kinetic energy of the wind turbine is required to be converted into electric energy, the output power of the wind turbine temporarily increases, and after the wind turbine operates at a new steady-state rotating speed, the output power of the wind turbine rapidly decreases. Therefore, the dynamic response speed of the existing wind turbine generator system must be designed in a compromise between improving the wind energy utilization rate and reducing the power fluctuation.
In the wind power system operation method based on the single-quadrant converter flux weakening control provided by the embodiment of the invention, the wind power machine operates at the rated rotation speed when the rotation speed of the variable frequency transformer is zero, the rotation speed of the wind power machine is reduced when the rotation speed of the variable frequency transformer is positively increased, and the wind power machine operates at the lowest rotation speed when the variable frequency transformer operates at the positive highest rotation speed; a rotor armature winding of a direct current motor in a variable frequency transformer adopts a single-quadrant driving converter consisting of a power switch tube and a freewheel diode to provide unipolar armature voltage and armature current; a stator exciting winding of a direct current motor in a variable frequency transformer adopts an exciting converter consisting of a power switch tube and a freewheel diode to provide unipolar exciting voltage and exciting current; the exciting converter outputs rated exciting current when the wind turbine runs at rated rotation speed, and the exciting current output by the exciting converter decreases when the rotation speed of the wind turbine decreases.
The rotational energy storage absorbed by the rapid rising of the rotational speed of the wind turbine, the gearbox and the synchronous generator can be partially compensated by the rotational energy storage released by the falling of the rotational speed of the variable frequency transformer; the rotational energy storage released by the rapid decrease of the rotational speed of the wind turbine, the gearbox and the synchronous generator can be partially compensated by the rotational energy storage absorbed by the increase of the rotational speed of the variable frequency transformer; when the rotating speed of the wind turbine rapidly responds to the change of wind speed so as to achieve maximum wind energy capture, the fluctuation of the output power of the wind power system is reduced.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention 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 technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A wind power system based on single-quadrant converter flux weakening control, comprising: the wind power generation system is characterized by comprising a wind power generator set, a variable frequency transformer, a step-down transformer and a power frequency power grid, wherein the variable frequency transformer comprises a doubly-fed motor, a direct-current motor, a single-quadrant driving converter, an excitation converter, a direct-current bus capacitor and a diode rectifier;
the rotor winding of the doubly-fed motor is connected with a wind generating set, the stator winding of the doubly-fed motor is connected with the power frequency power grid, and the doubly-fed motor is coaxially and mechanically connected with the direct-current motor;
one end of the single-quadrant driving converter is connected with a rotor armature winding of the direct current motor, and the other end of the single-quadrant driving converter is connected with the direct current bus capacitor;
one end of the excitation converter is connected with a stator excitation winding of the direct current motor, and the other end of the excitation converter is connected with the direct current bus capacitor;
the alternating current input end of the diode rectifier is connected with the power frequency power grid through the step-down transformer, and the direct current output end of the diode rectifier is connected with the direct current bus capacitor;
the single-quadrant driving converter is used for providing single-polarity armature voltage and armature current to a rotor armature winding of the direct-current motor, and the exciting converter is used for providing single-polarity exciting voltage and exciting current to a stator exciting winding of the direct-current motor.
2. The wind power system based on single-quadrant converter flux weakening control according to claim 1, wherein the single-quadrant driving converter comprises a first power switching tube and a first freewheeling diode;
the emitter of the first power switch tube is connected with the cathode of the first freewheel diode;
the collector of the first power switch tube and the anode of the first freewheeling diode are respectively connected with the anode and the cathode of the direct-current bus capacitor;
and the cathode and the anode of the first freewheeling diode are respectively connected with the anode and the cathode of the armature winding of the rotor of the direct current motor.
3. The wind power system based on single-quadrant converter flux weakening control according to claim 1, wherein the excitation converter comprises a second power switching tube and a second freewheeling diode;
the emitter of the second power switch tube is connected with the cathode of the second freewheel diode;
the collector electrode of the second power switch tube and the anode of the second freewheeling diode are respectively connected with the anode and the cathode of the direct-current bus capacitor;
and the cathode and the anode of the second follow current diode are respectively connected with the anode and the cathode of the stator exciting winding of the direct current motor.
4. A single-quadrant converter flux weakening control based wind power system as claimed in claim 1, wherein said diode rectifier comprises six rectifier diodes;
the six rectifier diodes are connected in parallel with the direct current bus capacitor after being connected in series in the same direction;
and three-phase wiring of the step-down transformer is respectively connected with the connecting parts of the rectifier diodes which are connected in series.
5. The wind power system based on single-quadrant converter flux weakening control according to claim 1, wherein the wind generating set comprises a wind turbine, a gearbox and a synchronous generator;
the wind turbine is mechanically connected with the synchronous generator through the gear box;
the stator winding of the synchronous generator is connected with the rotor winding of the doubly-fed motor.
6. The wind power system based on single-quadrant converter flux weakening control according to claim 1, wherein the single-quadrant driving converter adopts a double closed-loop control algorithm;
the proportional integral regulator of the rotating speed outer ring obtains a rotor armature winding current given value of the direct current motor according to the difference value between the rotating speed given value of the variable frequency transformer and the corresponding measured value, the upper limit of the rotor armature winding current given value is set to be the rated current of the single-quadrant driving converter, and the lower limit of the rotor armature winding current given value is set to be zero;
and the proportional-integral regulator of the current inner loop obtains the duty ratio of the single-quadrant driving converter according to the difference value between the given value of the current of the armature winding of the rotor of the direct-current motor and the corresponding measured value.
7. The wind power system based on single-quadrant converter flux weakening control according to claim 6, wherein the rotation speed given value of the variable frequency transformer is calculated specifically according to a real-time measured wind speed and maximum wind energy capturing control algorithm of the wind turbine.
8. The wind power system based on single-quadrant converter flux weakening control according to claim 1, wherein the excitation converter is controlled by an excitation current closed-loop control algorithm;
the proportional-integral regulator of the excitation converter calculates the duty ratio of the excitation converter according to the deviation between the given value of the stator excitation winding current of the direct-current motor and the corresponding measured value;
the exciting winding current given value is calculated specifically according to the real-time measurement rotating speed of the wind generating set.
9. The wind power system based on single-quadrant converter flux weakening control according to claim 1, wherein the wind power generator sets connected with the rotor windings of the doubly-fed motor are one or more than one set.
10. A method for operating a wind power system based on single-quadrant converter field weakening control, based on a wind power system based on single-quadrant converter field weakening control according to any one of claims 1 to 9, characterized by comprising:
when the wind speed rises, the single-quadrant driving converter and the exciting converter of the variable frequency transformer control the rotation speed of the direct current motor to drop, so that the rotation speed of the wind generating set rises, and simultaneously the rotation energy storage of the doubly-fed motor and the direct current motor is released to compensate the rotation energy storage of the wind generating set;
when the wind generating set operates at the rated rotation speed, the single-quadrant driving converter and the exciting converter of the variable-frequency transformer control the rotation speed of the direct-current motor to be zero;
when the wind speed is reduced, the single-quadrant driving converter and the exciting converter of the variable-frequency transformer control the rotation speed of the direct-current motor to be increased, so that the rotation speed of the wind generating set is reduced, and meanwhile, the rotation energy storage of the wind generating set is absorbed to the rotation energy storage of the doubly-fed motor and the direct-current motor; in the process that the rotating speed of the wind generating set is reduced along with the wind speed, if the control voltage required by the rotor armature winding of the direct current motor exceeds the safety voltage of the first power switch tube and the first freewheel diode in the single-quadrant drive converter, the exciting winding current given value of the exciting converter is reduced, and the maximum wind energy capture of the wind generating set in a low wind speed section is realized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710091005.3A CN106602611B (en) | 2017-02-20 | 2017-02-20 | Wind power system based on single-quadrant converter flux weakening control and operation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710091005.3A CN106602611B (en) | 2017-02-20 | 2017-02-20 | Wind power system based on single-quadrant converter flux weakening control and operation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106602611A CN106602611A (en) | 2017-04-26 |
| CN106602611B true CN106602611B (en) | 2023-05-05 |
Family
ID=58587817
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710091005.3A Active CN106602611B (en) | 2017-02-20 | 2017-02-20 | Wind power system based on single-quadrant converter flux weakening control and operation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106602611B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106887847B (en) * | 2017-04-28 | 2019-09-06 | 广东工业大学 | A kind of micro-capacitance sensor and its operation method of the control of variable frequency transformer direct load |
| CN113131494B (en) * | 2021-06-17 | 2021-08-24 | 广东电网有限责任公司佛山供电局 | Method, system, equipment and medium for controlling maximum capacity transmission of variable frequency transformer |
| CN113654203B (en) * | 2021-08-24 | 2022-10-04 | 广东电网有限责任公司 | Control method and device of three-phase alternating-current variable-frequency air conditioner |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102097826A (en) * | 2011-02-25 | 2011-06-15 | 南京航空航天大学 | Doubly salient electromagnetic wind power generation system structure and control method |
| CN106130076A (en) * | 2016-08-17 | 2016-11-16 | 青岛大学 | A kind of low voltage traversing control method for self-styled closed form electromagnetic coupled speed-regulating wind group of motors |
| CN106130075A (en) * | 2016-08-17 | 2016-11-16 | 青岛大学 | A kind of self-styled closed form electromagnetic coupled speed-regulating wind group of motors and control method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8405247B2 (en) * | 2010-12-16 | 2013-03-26 | General Electric Company | Method and apparatus for control of fault-induced delayed voltage recovery (FIDVR) with photovoltaic and other inverter-based devices |
-
2017
- 2017-02-20 CN CN201710091005.3A patent/CN106602611B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102097826A (en) * | 2011-02-25 | 2011-06-15 | 南京航空航天大学 | Doubly salient electromagnetic wind power generation system structure and control method |
| CN106130076A (en) * | 2016-08-17 | 2016-11-16 | 青岛大学 | A kind of low voltage traversing control method for self-styled closed form electromagnetic coupled speed-regulating wind group of motors |
| CN106130075A (en) * | 2016-08-17 | 2016-11-16 | 青岛大学 | A kind of self-styled closed form electromagnetic coupled speed-regulating wind group of motors and control method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106602611A (en) | 2017-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8698335B2 (en) | Low cost current source converters for power generation application | |
| Poddar et al. | Sensorless variable-speed controller for existing fixed-speed wind power generator with unity-power-factor operation | |
| CN104660129B (en) | Switch reluctance wind driven generator control system and method | |
| NO332673B1 (en) | Inverter | |
| CN104539206B (en) | Marine large-scale straight drive switching magnetic-resistance wind-driven generator power converter system | |
| CN102709945B (en) | Energy-storage wind power generation system with squirrel-cage generator | |
| Yang et al. | Application of a matrix converter for PMSG wind turbine generation system | |
| CN202652130U (en) | Motor drive system used for weaving machine direct main drive | |
| CN106602611B (en) | Wind power system based on single-quadrant converter flux weakening control and operation method thereof | |
| WO2013067800A1 (en) | Megawatt direct drive type squirrel-cage asynchronous generator ac-dc-ac wind generation system | |
| CN102684579A (en) | Motor drive system for direct main drive of weaving machine | |
| CN109962496B (en) | Offshore wind farm integrated topology design method based on high-voltage direct-current power transmission | |
| Luqman et al. | Analysis of variable speed wind energy conversion system with PMSG and Vienna rectifier | |
| CN202841050U (en) | Cascaded high-voltage inverter speed regulating system with energy feedback function | |
| Wei et al. | Analysis and comparison of current-source-converter-based medium-voltage PMSG wind energy conversion systems | |
| EP3961900A1 (en) | Hybrid capacitor bank for a power conversion assembly | |
| CN201869080U (en) | Flywheel energy storage motor device with changeable power supply structure | |
| Dai et al. | Low cost current source converter solutions for variable speed wind energy conversion systems | |
| Bayhan et al. | Active and reactive power control of grid connected permanent magnet synchronous generator in wind power conversion system | |
| Dongling et al. | Coordination control for offshore wind power sending through hybrid HVDC | |
| CN110661298A (en) | Medium-voltage variable-frequency wind power generation system and method based on cascade unit | |
| CN206727662U (en) | A kind of wind power system based on the control of single quadrant converter weak magnetic | |
| Yuan | Multilevel modular high power converters for 10MW wind turbines | |
| Chen et al. | Excitation for establishing voltage of switched reluctance generator at low rotor speed | |
| CN113783436B (en) | Full-power wind power converter and control method |
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 |