CN211981513U

CN211981513U - Three-level 1140V wind power double-fed converter

Info

Publication number: CN211981513U
Application number: CN202020433488.8U
Authority: CN
Inventors: 林周泉; 项峰; 洪敏�
Original assignee: Zhejiang Windey Co Ltd
Current assignee: Zhejiang Windey Co Ltd
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2020-11-20
Anticipated expiration: 2030-03-30

Abstract

The invention discloses a three-level 1140V wind power double-fed converter, which overcomes the problems of low generating efficiency and high electricity cost of a double-fed unit in the prior art, and comprises a transformer, a grid-connected cabinet module, a control cabinet module, a power cabinet module and a generator, wherein the output end of the transformer is connected with the input end of the grid-connected cabinet module, the output end of the grid-connected cabinet module is connected with the input end of the generator, the control end of the grid-connected cabinet module is connected with the input end of the power cabinet module, the power cabinet module is also connected with the control cabinet module, the output end of the generator is connected with the power cabinet module, and the rated. According to the invention, a 1140V three-level electric transmission technology is adopted to enable the output switch state combination of the frequency converter to be improved from 8 to 27, the output waveform of the converter is closer to a sine wave, the harmonic content is further reduced, the current is reduced by nearly 65% under the condition of the same unit power, the efficiency of an electric transmission system and a power transmission and transformation system is greatly improved, and the power consumption cost is reduced.

Description

Three-level 1140V wind power double-fed converter

Technical Field

The utility model belongs to the technical field of wind generating set electrical system and specifically relates to a three level 1140V wind-powered electricity generation double-fed converter that can realize lower harmonic, the electric energy transmission of higher voltage, converter efficiency can promote the unit generated energy.

Background

A wind power converter is an excitation device added on a rotor side in a double-fed wind power generator. The main function is that when the rotor speed n changes, the amplitude, phase, frequency and the like of excitation are controlled by the converter, so that the stator side can input constant frequency electricity to a power grid. At present, the outlet voltage of a land mainstream doubly-fed wind generating set is 690V, a main circuit of a converter adopts a two-level topological structure, and the converter of the two-level circuit has the characteristics that the main circuit structure is relatively simple and a control algorithm is easy to realize; but the defect is also obvious, the converter efficiency of the two-level circuit is relatively low, the maximum efficiency can only reach 96%, and the harmonic content of the output waveform is high.

For example, a "doubly-fed wind turbine system and a method for suppressing the rapid fluctuation of the grid voltage" disclosed in chinese patent literature has publication No. CN107196335A, a generator, a rotor-side converter, a grid-side inductor Lg, a capacitor C, a phase-locked loop, and a signal processor. The generator converts wind power resources into electric power to be transmitted to a power grid, the rotor-side converter controls rotor excitation voltage of the generator, the rotor-side converter and the grid-side converter form a two-level PWM converter which is back-to-back and connected through a direct-current link, variable-speed constant-frequency operation is achieved, the grid-side converter Lg plays a role in filtering, the phase-locked loop is provided for a controller of the rotor-side converter and the grid-side converter through collecting amplitude and phase of the voltage of the power grid, and the doubly-fed wind power generator is controlled to track the phase of the power grid and output required. Change the utility model discloses a traditional two level circuit, though can restrain the quick undulant but converter efficiency of grid voltage is low relatively, the highest 96% that can only reach, the waveform harmonic content of output simultaneously is great, can only export two levels of height, low, the generating efficiency is low.

SUMMERY OF THE UTILITY MODEL

The utility model relates to an overcome the problem that the double-fed unit generating efficiency low-power electricity of prior art is with high costs, a three level 1140V wind-powered electricity generation double-fed converter is provided, this kind of circuit can export height, low level and zero level, the output waveform more is close the sine wave, can realize lower harmonic, the electric energy transmission of higher voltage, make fan converter output phase voltage have-

Vdc

2, 0 and + Vdc 2 three level, bring higher generating efficiency, the efficiency of converter can promote to 98%, further promote the generated energy of unit.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a three level 1140V wind-powered electricity generation double-fed converter, includes the transformer, is incorporated into the power networks cabinet module, switch board module, power cabinet module and generator, the transformer output is connected with the cabinet module input that is incorporated into the power networks, and the cabinet module output that is incorporated into the power networks is connected with the generator input, and the cabinet module control end that is incorporated into the power networks is connected with power cabinet module input, and power cabinet module still is connected with the switch board module, and the generator output is connected with the power cabinet module, the generator stator rated output voltage of generator is 1140V, and the power cabinet module includes net side power module, machine side power module and direct current link, and net side power module and machine side power module are connected through.

The three-level 1140V electric transmission chain is applied to the technical field of double feeding, so that the output phase voltage of the fan frequency converter has three levels of-Vdc/2, 0 and + Vdc/2, higher power generation efficiency is brought, the efficiency of the converter can be improved to 98%, and the power generation capacity of a unit is further improved. By adopting a 1140V three-level electric transmission technology, the output switch state combination of the frequency converter of the double-fed fan is improved from 8 types to 27 types, the output waveform of the converter is closer to a sine wave, and the harmonic content is further reduced. Meanwhile, the three-level 1140V double-fed converter is adopted to increase the voltage of the fan from the traditional 690V to 1140V, the current is reduced by nearly 65% under the condition of the same unit power, the efficiency of an electric transmission system and a transmission and transformation system is greatly improved, and the power consumption cost is reduced. In addition, the scheme of the three-level converter can theoretically achieve 0 common-mode voltage, and fundamentally solves the problem that a motor bearing is corroded by the common-mode voltage.

Preferably, the grid-connected cabinet module comprises a main circuit breaker, a grid-connected contactor and a main contactor, wherein the input end of the main circuit breaker is connected with the output end of the transformer, the output end of the main circuit breaker is respectively connected with the input end of the grid-connected contactor and the input end of the main contactor, the output end of the grid-connected contactor is connected with the input end of the generator, and the output end of the main contactor is connected with the power cabinet module. The main breaker is connected to the 1140 primary side of the transformer.

Preferably, the control cabinet module comprises a converter interface system and a master control system, a control end of the master control system is connected with a controlled end of the converter interface system, and an output end of the converter interface system is connected with the power cabinet module. One end of the converter interface system is connected with the master control system, receives a control instruction of the master control system, and feeds back a real-time state signal of the double-fed converter to the master control system, the power cabinet module at the other end of the converter interface system completes driving and modulation of the power cabinet module, active power and reactive power of the unit are controlled, variable-speed constant-frequency power generation of the double-fed wind driven generator unit is realized, the master control system sends a control instruction of the power module to the converter interface system according to the actual operation condition of the unit, and receives a real-time state feedback signal of the double-fed converter.

Preferably, the power cabinet module further comprises an LC filter, a Chopper module, a machine side reactor and a Crowbar module, an input end of the LC filter is connected with the grid-connected cabinet module, the other end of the LC filter is connected with an input end of the grid-side power module, a direct current side of the grid-side power module is respectively connected with a direct current side of the Chopper module and a direct current side of the machine side power module, a controlled end of the grid-side power module and a controlled end of the machine side power module are both connected with an output end of the converter interface system, an output end of the machine side power module is respectively connected with an output end of the generator and the Crowbar module, the direct current link comprises a neutral point O, and the neutral point O is respectively connected with the grid-side. One end of the network side power module is connected with the network side reactor, the other end of the network side power module is connected with the machine side power module, and the network side power module can control the voltage of the direct current bus to be constant and adjust the power factor of the network side, so that the reactive power of the whole wind power generation system is adjusted more flexibly; one end of the machine side power module is connected with the grid side reactor, the other end of the machine side power module is connected with the machine side reactor, the machine side power module mainly provides generator exciting current, the current frequency of a rotor is controlled, and variable-speed constant-frequency power generation of the double-fed wind driven generator set is realized; the Chopper module is connected with a direct current bus between the network side power module and the machine side power module, and when the voltage of the direct current bus is abnormal, the Chopper module acts to control the direct current bus to be maintained in a normal range; one end of the machine side reactor is connected with the machine side power module, and the other end of the machine side reactor is connected with the generator rotor and the Crowbar module, so that the change rate of output voltage can be effectively reduced, the condition that the rotor bears peak voltage and du/dt electrical stress is improved, and the insulation life of the generator rotor is prolonged; the Crowbar module is connected with the machine side reactor and the generator rotor, and under the condition of sudden voltage drop of a power grid, the Crowbar module performs short circuit on a generator rotor winding, so that a bypass channel is provided for rotor current, overcurrent on the rotor side and overvoltage of a direct-current bus are inhibited, and the protection effect on a unit is realized.

Preferably, the LC filter includes a grid-side reactor and a grid-side capacitor, one end of the grid-side reactor is connected to the output end of the grid-connected cabinet module and the input end of the grid-side capacitor, the other end of the grid-side reactor is connected to the input end of the grid-side power module, and the LC filter is disposed between the transformer and the grid-side power module. And the grid-side reactor and the grid-side capacitor form an LC filter which is arranged between the transformer and the grid-side power module and is used for absorbing high-frequency components and preventing switching noise of the converter from polluting a power grid.

Preferably, the grid-side power module includes a U1 phase bridge arm, a V1 phase bridge arm, and a W1 phase bridge arm, each phase bridge arm includes four grid-side IGBT modules and two clamp diodes, the clamp diodes are all connected to the dc link and the dc side of the machine-side power module, the U1 phase bridge arm includes a grid-side IGBT module a1, a grid-side IGBT module a2, a grid-side IGBT module B1, a grid-side IGBT module B2, a diode E1, and a diode E4, the V1 phase bridge arm includes a grid-side IGBT module A3, a grid-side IGBT module A4, a grid-side IGBT module B3, a grid-side IGBT module B4, a diode E2, and a diode E5, and the W1 phase bridge arm includes a grid-side IGBT module a5, a grid-side IGBT module A6, a grid-side IGBT module B5, a grid-side IGBT module B6, a diode E3, and a diode E6. And a freewheeling diode is reversely connected in parallel in the grid-side IGBT module.

Preferably, the machine side power module comprises a U2 phase bridge arm, a V2 phase bridge arm and a W2 phase bridge arm, each phase bridge arm comprises four machine side IGBT modules and two clamping diodes, the clamping diodes are all connected with the direct current sides of the direct current link and the machine side power module, the U2 phase bridge arm comprises a machine side IGBT module C1, a machine side IGBT module C2, a machine side IGBT module D1, a machine side IGBT module D2, a diode F1 and a diode F4, the V2 phase bridge arm comprises a machine side IGBT module C3, a machine side IGBT module C4, a machine side IGBT module D3, a machine side IGBT module D4, a diode F2 and a diode F5, and the W1 phase bridge arm comprises a machine side IGBT module C5, a machine side IGBT module C6, a machine side IGBT module D5, a machine side IGBT module D6, a diode F3 and a diode F6. A freewheeling diode is connected in parallel in reverse inside each machine side IGBT module.

Preferably, the dc link includes a capacitor CC1, a capacitor CC2, a dc Chopper module CP1 and a dc Chopper module CP2, one end of the capacitor CC1 is connected to the positive electrode of the dc link and one end of the dc Chopper module CP1, one end of the capacitor CC2 is connected to the negative electrode of the dc link and one end of the dc Chopper module CP2, and a neutral point O of the dc link is connected to the other end of the capacitor CC1, the other end of the dc Chopper module CP1, the other end of the capacitor CC2 and the other end of the dc Chopper module CP2, respectively.

Preferably, the grid-side IGBT module a1 and the grid-side IGBT module B2 in the U1-phase arm are main switches, and the grid-side IGBT module a2 and the grid-side IGBT module B1 are auxiliary switches. The whole topological structure has 24 IGBT modules, all the IGBT modules have the same requirements on voltage resistance, current and the like, and the bearing voltage is 1/2 of the direct-current side bus voltage. The network side power module U1 phase arm a1 and B2 are main switches, a2 and B1 are auxiliary switches, and by turning on (a 1, a 2), (a 2, B1), (B1, B2), the IGBT modules have 27 kinds of switching states in total. The output phase voltage of the U1 phase is + Vdc/2, 0, -Vdc/2. Similarly, the output phase voltages of the phases V1 and W1 of the grid-side power module and the machine-side power module are three levels of + Vdc/2, 0 and-Vdc/2.

Therefore, the utility model discloses following beneficial effect has:

1. the three-level 1140V electric transmission chain is applied to the technical field of double feeding, so that the output phase voltage of the fan frequency converter has three levels of-Vdc/2, 0 and + Vdc/2, higher power generation efficiency is brought, the efficiency of the converter can be improved to 98%, and the power generation capacity of a unit is further improved. By adopting a 1140V three-level electric transmission technology, the output switch state combination of the frequency converter of the double-fed fan is improved from 8 types to 27 types, the output waveform of the converter is closer to a sine wave, and the harmonic content is further reduced. Meanwhile, the three-level 1140V double-fed converter is adopted to increase the voltage of the fan from the traditional 690V to 1140V, the current is reduced by nearly 65% under the condition of the same unit power, the efficiency of an electric transmission system and a transmission and transformation system is greatly improved, and the power consumption cost is reduced. In addition, the scheme of the three-level converter can theoretically achieve 0 common-mode voltage, and fundamentally solves the problem that a motor bearing is corroded by the common-mode voltage;

2. the LC filter is arranged between the transformer and the grid side power module and used for absorbing high-frequency components and preventing switching noise of the converter from polluting a power grid; the output waveform is closer to a sine wave, and electric energy transmission with lower harmonic wave and higher voltage can be realized;

3. one end of the converter interface system is connected with the master control system, receives a control instruction of the master control system and feeds back a real-time state signal of the double-fed converter to the master control system, the other end of the converter interface system is provided with a power cabinet module to drive and modulate the power cabinet module and control the active power and the reactive power of the unit, so that the variable-speed constant-frequency power generation of the double-fed wind driven generator unit is realized, and the master control system sends a control instruction of the power module to the converter interface system according to the actual operation condition of the unit and receives the real-time state feedback signal of the;

4. one end of the network side power module is connected with the network side reactor, the other end of the network side power module is connected with the machine side power module, and the network side power module can control the voltage of the direct current bus to be constant and adjust the power factor of the network side, so that the reactive power of the whole wind power generation system is adjusted more flexibly; one end of the machine side power module is connected with the grid side reactor, the other end of the machine side power module is connected with the machine side reactor, the machine side power module mainly provides generator exciting current, the current frequency of a rotor is controlled, and variable-speed constant-frequency power generation of the double-fed wind driven generator set is realized; the Chopper module is connected with a direct current bus between the network side power module and the machine side power module, and when the voltage of the direct current bus is abnormal, the Chopper module acts to control the direct current bus to be maintained in a normal range; one end of the machine side reactor is connected with the machine side power module, and the other end of the machine side reactor is connected with the generator rotor and the Crowbar module, so that the change rate of output voltage can be effectively reduced, the condition that the rotor bears peak voltage and du/dt electrical stress is improved, and the insulation life of the generator rotor is prolonged; the Crowbar module is connected with the machine side reactor and the generator rotor, and under the condition of sudden voltage drop of a power grid, the Crowbar module performs short circuit on a generator rotor winding, provides a bypass channel for rotor current, inhibits overcurrent at the rotor side and overvoltage of a direct-current bus, and realizes the protection effect on a unit; the common-mode voltage of 0 can be achieved, and the problem that the motor bearing is corroded by the common-mode voltage is solved fundamentally.

Drawings

Fig. 1 is a schematic view of the external structure of the present invention.

Fig. 2 is a block diagram of the present invention.

Fig. 3 is a block diagram of the main topology of the power module of the present invention.

In the figure: 1. the system comprises a grid-connected cabinet module 11, a main circuit breaker 12, a grid-connected contactor 13, a main contactor 2, a control cabinet module 21, a converter interface system 22, a main control system 3, a power cabinet module 31, an LC filter 311, a grid-side reactor 312, a grid-side capacitor 32, a Chopper module 33, a grid-side power module 34, a machine-side power module 35, a machine-side reactor 36, a Crowbar module 37, a direct-current link 4, a transformer 5 and a generator.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description.

Example 1:

in this embodiment, as shown in fig. 1 and fig. 2, a three-level 1140V wind power double-fed converter includes a grid-connected cabinet module, a control cabinet module and a power cabinet module, which are sequentially connected with each other, and an internal topology structure includes the grid-connected cabinet module, the control cabinet module, the power cabinet module, a transformer and a generator, where an output end of the transformer is connected with an input end of the grid-connected cabinet module, an output end of the grid-connected cabinet module is connected with an input end of the generator, a control end of the grid-connected cabinet module is connected with an input end of the power cabinet module, the power cabinet module is further connected with the control cabinet module, an output end of the generator is connected; the grid-connected cabinet module comprises a main circuit breaker 11, a grid-connected contactor 12 and a main contactor 13, the control cabinet module 2 comprises a converter interface system 21 and a main control system 22, and the power cabinet module 3 further comprises an LC filter 31, a Chopper module 32, a machine side reactor 35, a Crowbar module 36, a network side power module 33, a machine side power module 34 and a direct current link 37; the input end of a main circuit breaker 11 is connected with the output end of a transformer 4, the output end of a main circuit breaker 2 is respectively connected with the input end of a grid-connected contactor 12 and the input end of a main contactor 13, the output end of the grid-connected contactor 12 is connected with the input end of a generator 5, the output end of the main contactor 13 is connected with a power cabinet module 3, the control end of a main control system 22 is connected with the controlled end of a converter interface system 21, the output end of the converter interface system 21 is connected with the power cabinet module 3, a grid side power module 33 and a machine side power module 34 are connected through a direct current link, the input end of an LC filter 31 is connected with a grid-connected cabinet module 1, the other end of the LC filter 31 is connected with the input end of the grid side power module 33, the direct current side of the grid side power module 33 is respectively connected with the direct current side of a Chopper module, the output end of the machine side power module 34 is respectively connected with the output end of the generator 5 and the Crowbar module 36, and the direct current link 37 comprises a neutral point O which is respectively connected with the network side power module 33 and the machine side power module 34.

The LC filter 31 comprises a grid-side reactor 311 and a grid-side capacitor 312, one end of the grid-side reactor 311 is respectively connected with the output end of the grid-connected cabinet module 1 and the input end of the grid-side capacitor 312, the other end of the grid-side reactor 311 is connected with the input end of the grid-side power module 33, the LC filter 31 is arranged between the transformer 4 and the grid-side power module 33, the grid-side reactor 311 and the grid-side capacitor 312 form the LC filter 31, and the LC filter is arranged between the transformer 4 and the grid-side power module 33 and used for absorbing high-frequency components and preventing switching noise of the converter from polluting.

Example 2:

in this embodiment, as shown in fig. 3, a grid-side power module 33 is connected to a machine-side power module 34 through a dc link 37, the grid-side power module 33 is composed of three phase bridge arms, the machine-side power module 34 is also composed of three phase bridge arms, each phase bridge arm is composed of four IGBT modules and two clamping diodes, the dc link 37 is composed of two capacitors, a dc Chopper module CP1 and a dc Chopper module CP2, one end of the capacitor CC1 is connected to the positive electrode of the dc link 37 and one end of the dc Chopper module CP1, one end of the capacitor CC2 is connected to the negative electrode of the dc link 37 and one end of the dc Chopper module CP2, a neutral point O of the dc link 37 is connected to the other end of the capacitor CC1, the other end of the dc Chopper module CP1, the other end of the capacitor CC2 and the other end of the dc Chopper module CP2, and a neutral point O of the dc link 37 is connected to the clamping diodes of the grid-side power module 33 and the machine-side power module 34, and in addition, a freewheeling diode is connected in parallel in all the IGBT modules in an opposite direction.

The grid-side power module 33 comprises a U1 phase bridge arm, a V1 phase bridge arm and a W1 phase bridge arm, clamping diodes are connected with a direct-current link 37 and a direct-current side of the machine-side power module 33, the U1 phase bridge arm comprises a grid-side IGBT module A1, a grid-side IGBT module A2, a grid-side IGBT module B1, a grid-side IGBT module B2, a diode E1 and a diode E4, the V1 phase bridge arm comprises a grid-side IGBT module A3, a grid-side IGBT module A4, a grid-side IGBT module B3, a grid-side IGBT module B4, a diode E2 and a diode E5, and the W1 phase bridge arm comprises a grid-side IGBT module A5, a grid-side IGBT module A6, a grid-side IGBT module B5, a grid-side IGBT module B6, a diode E3 and a diode E6.

The power module 34 comprises a U2 phase bridge arm, a V2 phase bridge arm and a W2 phase bridge arm, each phase bridge arm comprises four machine side IGBT modules and two clamping diodes, the clamping diodes are connected with the direct current sides of the direct current link 37 and the machine side power module 33, the U2 phase bridge arm comprises a machine side IGBT module C1, a machine side IGBT module C2, a machine side IGBT module D1, a machine side IGBT module D2, a diode F1 and a diode F4, the V2 phase bridge arm comprises a machine side IGBT module C3, a machine side IGBT module C4, a machine side IGBT module D3, a machine side IGBT module D4, a diode F2 and a diode F5, and the W1 phase bridge arm comprises a machine side IGBT module C5, a machine side IGBT module C6, a machine side IGBT module D5, a machine side IGBT module D6, a diode F3 and a diode F6.

The grid side IGBT module A1 and the grid side IGBT module B2 in the U1 phase bridge arm are main switches, and the grid side IGBT module A2 and the grid side IGBT module B1 are auxiliary switches. The whole topological structure has 24 IGBT modules, all the IGBT modules have the same requirements on voltage resistance, current and the like, and the bearing voltage is 1/2 of the direct-current side bus voltage. The bridge arm A1 and B2 of the network side power module U1 are main switches, A2 and B1 are auxiliary switches, and the switching states of the IGBT modules are totally 27 by turning on (A1, A2), (A2, B1), (B1 and B2). The output phase voltage of the U1 phase is + Vdc/2, 0, -Vdc/2. Similarly, the output phase voltages of the phases V1 and W1 of the grid-side power module and the machine-side power module are three levels of + Vdc/2, 0 and-Vdc/2.

The utility model discloses use three level 1140V electric transmission chain to double-fed technical field for fan frequency converter output phase voltage has-

Vdc

2, 0 and + Vdc 2 three level, brings higher generating efficiency, and the efficiency of converter can promote to 98%, further promotes the generated energy of unit. By adopting a 1140V three-level electric transmission technology, the output switch state combination of the frequency converter of the double-fed fan is improved from 8 types to 27 types, the output waveform of the converter is closer to a sine wave, and the harmonic content is further reduced. Meanwhile, the three-level 1140V double-fed converter is adopted to increase the voltage of the fan from the traditional 690V to 1140V, the current is reduced by nearly 65% under the condition of the same unit power, the efficiency of an electric transmission system and a transmission and transformation system is greatly improved, and the power consumption cost is reduced. In addition, the scheme of the three-level converter can theoretically achieve 0 common-mode voltage, and fundamentally solves the problem that a motor bearing is corroded by the common-mode voltage; the LC filter is arranged between the transformer and the grid side power module and used for absorbing high-frequency components and preventing switching noise of the converter from polluting a power grid; the output waveform is closer to a sine wave, and electric energy transmission with lower harmonic wave and higher voltage can be realized; one end of the converter interface system is connected with the master control system, receives a control instruction of the master control system and feeds back a real-time state signal of the double-fed converter to the master control system, the other end of the converter interface system is provided with a power cabinet module to drive and modulate the power cabinet module and control the active power and the reactive power of the unit, so that the variable-speed constant-frequency power generation of the double-fed wind driven generator unit is realized, and the master control system sends a control instruction of the power module to the converter interface system according to the actual operation condition of the unit and receives the real-time state feedback signal of the; one end of the network side power module is connected with the network side reactor, the other end of the network side power module is connected with the machine side power module, and the network side power module can control the voltage of the direct current bus to be constant and adjust the power factor of the network side, so that the reactive power of the whole wind power generation system is adjusted more flexibly; one end of the machine side power module is connected with the grid side reactor, the other end of the machine side power module is connected with the machine side reactor, the machine side power module mainly provides generator exciting current, the current frequency of a rotor is controlled, and variable-speed constant-frequency power generation of the double-fed wind driven generator set is realized; the Chopper module is connected with a direct current bus between the network side power module and the machine side power module, and when the voltage of the direct current bus is abnormal, the Chopper module acts to control the direct current bus to be maintained in a normal range; one end of the machine side reactor is connected with the machine side power module, and the other end of the machine side reactor is connected with the generator rotor and the Crowbar module, so that the change rate of output voltage can be effectively reduced, the condition that the rotor bears peak voltage and du/dt electrical stress is improved, and the insulation life of the generator rotor is prolonged; the Crowbar module is connected with the machine side reactor and the generator rotor, and under the condition of sudden voltage drop of a power grid, the Crowbar module performs short circuit on a generator rotor winding, provides a bypass channel for rotor current, inhibits overcurrent at the rotor side and overvoltage of a direct-current bus, and realizes the protection effect on a unit; the common-mode voltage of 0 can be achieved, and the problem that the motor bearing is corroded by the common-mode voltage is solved fundamentally.

The above embodiments are only used for further explanation of the present invention, and it is not understood that the present invention is limited by the protection scope of the present invention, and the technical engineers in the field are right according to the above contents of the present invention.

Claims

1. A three-level 1140V wind power double-fed converter comprises a transformer (4), it is characterized by also comprising a grid-connected cabinet module (1), a control cabinet module (2), a power cabinet module (3) and a generator (5), the output end of the transformer (4) is connected with the input end of the grid-connected cabinet module (1), the output end of the grid-connected cabinet module (1) is connected with the input end of a generator (5), the control end of the grid-connected cabinet module (1) is connected with the input end of a power cabinet module (3), the power cabinet module (3) is also connected with a control cabinet module (2), the output end of the generator (5) is connected with the power cabinet module (3), the rated output voltage of a generator stator of the generator (5) is 1140V, the power cabinet module (3) comprises a grid side power module (33), a machine side power module (34) and a direct current link (37), and the grid side power module (33) is connected with the machine side power module (34) through the direct current link (37).

2. A three-level 1140V wind power double-fed converter according to claim 1, wherein the grid-connected cabinet module (1) comprises a main circuit breaker (11), a grid-connected contactor (12) and a main contactor (13), wherein an input end of the main circuit breaker (11) is connected with an output end of the transformer (4), an output end of the main circuit breaker (11) is respectively connected with an input end of the grid-connected contactor (12) and an input end of the main contactor (13), an output end of the grid-connected contactor (12) is connected with an input end of the generator (5), and an output end of the main contactor (13) is connected with the power cabinet module (3).

3. A three-level 1140V wind power doubly-fed converter according to claim 1, characterized in that said control cabinet module (2) comprises a converter interface system (21) and a master control system (22), wherein a control end of the master control system (22) is connected to a controlled end of the converter interface system (21), and an output end of the converter interface system (21) is connected to the power cabinet module (3).

4. A three-level 1140V wind power double-fed converter according to claim 1 or 3, wherein the power cabinet module (3) further comprises an LC filter (31), a Chopper module (32), a machine side reactor (35) and a Crowbar module (36), an input end of the LC filter (31) is connected to the grid-connected cabinet module (1), another end of the LC filter (31) is connected to an input end of a grid-side power module (33), a direct current side of the grid-side power module (33) is respectively connected to the Chopper module (32) and a direct current side of the machine side power module (34), a controlled end of the grid-side power module (33) and a controlled end of the machine side power module (34) are both connected to an output end of the converter interface system (21), an output end of the machine side power module (34) is respectively connected to an output end of the generator (5) and the Crowbar module (36), the direct current link (37) comprises a neutral point O, the neutral point O is connected to the grid-side power module (33) and the machine-side power module (34), respectively.

5. A three-level 1140V wind power double-fed converter according to claim 4, characterized in that said LC filter (31) comprises a grid-side reactor (311) and a grid-side capacitor (312), one end of the grid-side reactor (311) is connected to the output end of the grid-connected cabinet module (1) and the input end of the grid-side capacitor (312), the other end of the grid-side reactor (311) is connected to the input end of the grid-side power module (33), and the LC filter (31) is placed between the transformer (4) and the grid-side power module (33).

6. A three-level 1140V wind power doubly-fed converter according to claim 4, the grid-side power module (33) comprises a U1 phase bridge arm, a V1 phase bridge arm and a W1 phase bridge arm, each phase bridge arm comprises four grid-side IGBT modules and two clamping diodes, the clamping diodes are connected with a direct current link (37) and the direct current side of the machine side power module (34), the U1 phase bridge arm comprises a net side IGBT module A1, a net side IGBT module A2, a net side IGBT module B1, a net side IGBT module B2, a diode E1 and a diode E4, the V1 phase bridge arm comprises a net side IGBT module A3, a net side IGBT module A4, a net side IGBT module B3, a net side IGBT module B4, a diode E2 and a diode E5, the W1 phase arm comprises a net side IGBT module A5, a net side IGBT module A6, a net side IGBT module B5, a net side IGBT module B6, a diode E3 and a diode E6.

7. A three-level 1140V wind power double-fed converter according to claim 4, characterized in that the machine side power module (34) comprises a U2 phase leg, a V2 phase leg and a W2 phase leg, each phase leg comprises a four machine side IGBT module and two clamping diodes, the clamping diodes are connected with the DC link (37) and the DC side of the machine side power module (34), the U2 phase leg comprises a machine side IGBT module C1, a machine side IGBT module C2, a machine side IGBT module D1, a machine side IGBT module D2, a diode F1 and a diode F4, the V2 phase leg comprises a machine side IGBT module C3, a machine side IGBT module C4, a machine side IGBT module D3, a machine side IGBT module D4, a diode F2 and a diode F5, and the W2 phase leg comprises a machine side IGBT module C5, a machine side IGBT module 6, a machine side IGBT module D5, a machine side IGBT module D6, a diode F3 and a diode F6.

8. The three-level 1140V wind power double-fed converter according to claim 4, wherein the DC link (37) comprises a capacitor CC1, a capacitor CC2, a DC Chopper module CP1 and a DC Chopper module CP2, one end of the capacitor CC1 is connected with the positive electrode of the DC link (37) and one end of the DC Chopper module CP1, one end of the capacitor CC2 is connected with the negative electrode of the DC link (37) and one end of the DC Chopper module CP2, and the neutral point O of the DC link (37) is respectively connected with the other end of the capacitor CC1, the other end of the DC Chopper module CP1, the other end of the capacitor CC2 and the other end of the DC Chopper module CP 2.

9. The three-level 1140V wind power double-fed converter according to claim 6, wherein the U1 phase bridge arm medium grid side IGBT module A1 and the grid side IGBT module B2 are main switches, and the grid side IGBT module A2 and the grid side IGBT module B1 are auxiliary switches.