阅读说明：本技术 基于模块化多电平变换器的双三相开绕组风力发电系统 (Double three-phase open winding wind power generation system based on modular multilevel converter ) 是由 贺明智 陈彦丞 王学庆 杨成 王指香 于 2021-01-27 设计创作，主要内容包括：本发明公开了一种基于模块化多电平变换器的双三相开绕组风力发电系统,包括双三相开绕组永磁同步风力发电机以及模块化多电平变换器,所述模块化多电平变换器包括多个模块化多电平变换器子模块,每一个所述三相开绕组永磁同步发电机的三相开绕组的两端依次串联多个所述模块化多电平变换器子模块后分别连接至直流母线的正极和负极,所述直流母线的正极和负极之间还设有直流母线电容。本发明旨在为风力发电领域提供一种高电压等级下的大容量、高功率密度、高可靠的解决方案,以使得风力发电的安全性、稳定性与高效性得到提升。(The invention discloses a double three-phase open winding wind power generation system based on a modular multilevel converter, which comprises a double three-phase open winding permanent magnet synchronous wind power generator and the modular multilevel converter, wherein the modular multilevel converter comprises a plurality of modular multilevel converter sub-modules, two ends of a three-phase open winding of each three-phase open winding permanent magnet synchronous generator are sequentially connected with the modular multilevel converter sub-modules in series and then are respectively connected to the positive pole and the negative pole of a direct current bus, and a direct current bus capacitor is arranged between the positive pole and the negative pole of the direct current bus. The invention aims to provide a high-capacity, high-power-density and high-reliability solution under a high voltage level for the field of wind power generation, so that the safety, stability and high efficiency of wind power generation are improved.)

1. The double three-phase open-winding wind power generation system based on the modular multilevel converter is characterized by comprising the modular multilevel converter and a pair of three-phase open-winding permanent magnet synchronous wind power generators, wherein the modular multilevel converter comprises a plurality of modular multilevel converter sub-modules, two ends of a three-phase open winding of each three-phase open-winding permanent magnet synchronous wind power generator are sequentially connected with the modular multilevel converter sub-modules in series and then are respectively connected to the positive pole and the negative pole of a direct current bus, and a direct current bus capacitor is further arranged between the positive pole and the negative pole of the direct current bus.

2. The double three-phase open-winding wind power generation system based on the modular multilevel converter according to claim 1, wherein two sets of three-phase open-winding permanent magnet synchronous wind power generators are spatially different from each other by 30 degrees.

3. The modular multilevel converter based dual three-phase open winding wind power generation system of claim 1, wherein the modular multilevel converter sub-module is one of a modular multilevel converter half-bridge sub-module, a modular multilevel converter full-bridge sub-module, a modular multilevel converter diode clamped sub-module, or a modular multilevel converter clamped bi-sub-module.

Technical Field

The invention relates to the technical field of renewable energy wind power generation, in particular to a double three-phase open winding wind power generation system based on a modular multilevel converter.

Background

With the depletion of fossil fuels and the acceleration of global warming, renewable energy has become a new choice to meet the demand of social energy. Wind power is an important clean renewable energy source and is gradually paid more and more attention, and researches in the related field of wind power are greatly advanced. Compared with a small wind power generation set, the large wind power generator can obtain more wind power generation capacity at lower unit installation and maintenance cost. As a result, the capacity and scale of wind power plants has increased exponentially over the past decades.

The continuous increase of the capacity of the wind generating set also puts higher requirements on power electronic conversion devices. Therefore, research on power electronic converters and wind driven generators with high power density, high voltage class and large capacity applied to wind power generation has become a research direction with important engineering significance in the field of new energy power generation.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a double three-phase open winding wind power generation system based on a modular multilevel converter, and aims to provide a high-capacity, high-power-density and high-reliability solution under a high voltage level for the field of wind power generation, so that the safety, stability and high efficiency of wind power generation are improved.

In order to achieve the purpose, the invention adopts the technical scheme that: the utility model provides a two three-phase open winding wind power generation system based on modularization multilevel converter, includes two three-phase open winding permanent magnet synchronous wind power generator and modularization multilevel converter, modularization multilevel converter includes a plurality of modularization multilevel converter submodule pieces, each the two ends of the three-phase open winding of three-phase open winding permanent magnet synchronous generator connect gradually a plurality of behind the modularization multilevel converter submodule piece be connected to the positive pole and the negative pole of direct current bus respectively, still be equipped with direct current bus capacitance between the positive pole and the negative pole of direct current bus.

Preferably, two sets of three-phase open windings of the double three-phase open winding permanent magnet synchronous wind driven generator are different in space by 30 degrees.

Preferably, the modular multilevel converter sub-module is a modular multilevel converter half-bridge sub-module, a modular multilevel converter full-bridge sub-module, a modular multilevel converter diode clamping sub-module or a modular multilevel converter clamping bi-sub-module.

The invention mainly comprises a double three-phase open winding permanent magnet synchronous generator, a modular multilevel converter with each bridge arm comprising n modular multilevel converter sub-modules, a direct current bus and a direct current bus capacitor; the modularized multi-level converter structure adopted by the invention omits a bridge arm reactor in the traditional modularized multi-level converter, and reuses the inductance in the double three-phase open-winding permanent magnet synchronous generator, thereby simplifying the system structure, reducing the system cost and improving the system power density.

According to the adopted double three-phase permanent magnet synchronous wind driven generator, two sets of three-phase open windings are different in space by 30 degrees in electric angle, and the two sets of three-phase windings are connected in an open winding mode, so that the current stress and the voltage stress of a wind power generation system can be improved, and the power level of the system is greatly improved. When the double three-phase permanent magnet synchronous wind driven generator has a phase failure, the rest five-phase generator winding can still continue to generate power, so that the power output of the wind driven generator winding under the phase failure can be ensured to a greater extent, and the reliability of the system is improved.

The modular multilevel converter adopted by the invention has higher system redundancy characteristic, and after the modular multilevel converter has short circuit or open circuit fault, the system can keep normal output of full power by isolating fault modular multilevel converter sub-modules and matching with the flexibility of open winding connection mode modulation, thereby improving the reliability of the whole wind power generation system.

The invention has the beneficial effects that:

1. the permanent magnet synchronous wind driven generator adopts a double three-phase winding structure, and two sets of three-phase open windings are different in space by 30 degrees in electric angle. The capacity and the power density of the power generation system can be greatly improved, and when one phase of the power generation system fails, the rest five-phase generator windings can still work normally, so that the reliability of the wind power generation system is greatly improved.

2. The two sets of three-phase windings of the permanent magnet synchronous wind driven generator adopt an open winding connection mode, and a plurality of groups of converters at two ends of the windings can be respectively controlled, so that various control strategies can be realized, and the characteristic of flexibility of the control method is embodied.

3. Compared with the traditional modularized multi-level converter, the modularized multi-level converter provided by the invention has the advantages that the winding inductance in the double three-phase open winding permanent magnet synchronous wind driven generator is multiplexed, and the bridge arm inductance in each bridge arm is omitted, so that the number of elements is reduced, the system structure is simplified, the manufacturing cost is reduced, and the power density of the system is improved.

4. The modular multilevel converter is adopted, the voltage level of the wind power generation system can be flexibly improved by adjusting the number of the sub-modules of the converter, and the modular multilevel converter has stronger capacity expansion capability and can be suitable for the wind power generation working environment under higher voltage level.

5. The invention adopts the modularized multi-level converter, when a certain submodule of the converter breaks down, the system can isolate the broken submodule in time and continue to maintain normal output, thereby improving the reliability of the output power of the wind power generation system.

Drawings

FIG. 1 is a circuit configuration diagram according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a double three-phase open winding permanent magnet synchronous wind power generation system according to an embodiment of the invention;

fig. 3 is a topology diagram of a sub-module of the modular multilevel converter according to an embodiment of the present invention.

Reference numerals:

1. the three-phase open winding type inverter comprises a three-phase open winding, 2, a modular multilevel converter, 3, a modular multilevel converter submodule, 4, a direct current bus, 5 and a direct current bus capacitor.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Examples

As shown in fig. 1, a double three-phase open-winding wind power generation system based on a modular multilevel converter comprises a double three-phase open-winding permanent magnet synchronous wind power generator and a modular multilevel converter 2, wherein the modular multilevel converter 2 comprises a plurality of modular multilevel converter sub-modules 3, two ends of a three-phase open winding 1 of each three-phase open-winding permanent magnet synchronous generator are sequentially connected in series with the plurality of modular multilevel converter sub-modules 3 and then respectively connected to a positive electrode and a negative electrode of a direct current bus 4, and a direct current bus capacitor 5 is further arranged between the positive electrode and the negative electrode of the direct current bus 4.

In this embodiment, two sets of three-phase open windings 1 of the double three-phase open winding permanent magnet synchronous wind driven generator are spatially different from each other by 30 degrees.

In this embodiment, the modular multilevel converter sub-module 3 is a modular multilevel converter half-bridge sub-module, a modular multilevel converter full-bridge sub-module, a modular multilevel converter diode clamping sub-module, or a modular multilevel converter clamping bi-sub-module.

The present embodiment is further illustrated below:

referring to fig. 1 again, in the modularized multi-level based dual three-phase open winding permanent magnet synchronous wind power generation system, the fan drives the three-phase open winding 1 of the wind power generation system to rotate, and the dual three-phase open winding a₁B₁C₁A₂B₂C₂And D₁E₁F₁D₂E₂F₂The generated alternating electromotive force and alternating current are respectively rectified by the upper and lower bridge arms of the modular multilevel converter 2, so that the alternating electromotive force and the alternating current are converted into constant direct current. In the embodiment, the double three-phase open winding permanent magnet synchronous generator is combined with the modular multilevel converter 2, so that the advantages of two schemes are achieved; the system has higher redundancy, higher reliability, higher flexibility and expandability while providing larger capacity and higher power density. When the double three-phase open winding permanent magnet synchronous wind driven generator is in a normal working state, because the two groups of three-phase open windings 1 both adopt the open winding connection mode, an independent control strategy can be implemented on each phase of winding, and the flexibility of the control mode of a wind power generation system is improved; when a certain phase winding in the double three-phase open winding permanent magnet synchronous generator fails, the rest phases of windings can still work normally due to the characteristic of independent control of each winding, so that the power output of the wind power generation system is kept. Similarly, because the wind power generation system adopts the topological structure of the modular multilevel converter 2, different types and different numbers of modular multilevel converter sub-modules 3 can be freely selected as basic units of the modular multilevel converter 2 for cascade connection, thereby flexibly adjusting the capacity and the output voltage grade of the converter and having good expandability; and then corresponding control strategies are carried out on the modular multilevel converters 2 at the two sides, so that the flexible control of the modular multilevel converters 2 is realized. The modular multilevel converter 2 has high redundancy, and when one module fails or abnormally operates, the modular multilevel converter system can isolate the fault modular multilevel converter sub-module 3 and control the other modular multilevel converter sub-modules 3 to keep a normal working state; thereby maintaining normal power transmission of the systemTherefore, the fault tolerance rate and the reliability of the system are greatly improved, and the normal operation of the wind power generation system is guaranteed.

As shown in fig. 2, in the double three-phase open winding permanent magnet synchronous wind power generation system, the blades of the wind power generation set rotate under the push of wind power, and the double three-phase open winding 1 of the set cuts the magnetic field generated by the permanent magnet, thereby generating six-phase induced electromotive force in the winding. The two groups of three-phase open windings 1 are connected in an open winding mode, and the difference between the windings is 30 degrees in electrical angle. The two groups of three-phase open windings 1 are connected with the modular multilevel converter 1 through the alternating current bus, and then the modular multilevel converter 1 obtains direct current output with constant voltage on the direct current bus 4. The permanent magnet synchronous wind driven generator in the embodiment adopts a double three-phase open winding mode for connection, the number of windings is doubled compared with that of a single three-phase winding generator, and the maximum current allowed by the windings is greatly increased, so that the system power generation capacity is doubled compared with that of a single winding generator, and larger power generation power output can be obtained. In addition, the double three-phase open winding permanent magnet synchronous wind driven generator is fused with the modular multilevel converter 2, so that the system voltage level and the single-machine generated power level can be further improved.

Fig. 3 shows a topological block diagram of several common modular multilevel converter sub-modules 3. The modular multilevel converter half-bridge submodule (a) can output two different levels, has the characteristics of simple structure and few used devices, and is most widely applied; (b) the modular multi-level converter is a full-bridge submodule, a single full-bridge submodule can output 3 different levels, output voltage can contain two different polarities, fault current can be blocked, and the modular multi-level converter is applied to bipolar voltage output occasions; (c) the modular multilevel converter is a T-shaped multilevel submodule, a single diode clamping submodule can output 3 different levels, the control is relatively simple, and the fault current cutting capability is not provided; (d) for the modular multilevel converter clamping dual sub-module, a single clamping dual sub-module can output 4 different levels, and the modular multilevel converter clamping dual sub-module has the function of clearing bidirectional current faults, but the corresponding control complexity is higher. In the above several modular multilevel converter sub-modules, the capacitors of the modular multilevel converter sub-modules are controlled to be charged and discharged by controlling the on and off of the switching tubes. And a plurality of same or different modular multilevel converter sub-modules are cascaded, and the required direct current output voltage can be obtained on the direct current bus 4 by controlling the connection and the disconnection of each sub-module. In summary, the power generation system provided in this embodiment adopts the modular multilevel converter 2, and can adopt the modular multilevel converter sub-module 3 suitable for the corresponding scenario according to the actual application requirement.

The above-mentioned embodiments only express the specific embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.