阅读说明：本技术 基于混合开关的级联对称飞跨电容器式拓扑静态补偿器 (Cascade symmetrical flying capacitor type topological static compensator based on hybrid switch ) 是由 穆罕默德·胡马云 于 2021-01-19 设计创作，主要内容包括：本发明涉及一种基于混合开关的级联对称飞跨电容器式拓扑静态补偿器,包括串联在一起的对称飞跨电容器模块和耦合电感器；所述对称飞跨电容器模块包括三组串联在一起的模块单元组成；所述模块单元包括第一开关对组、第二开关对组和第三开关对组组成,所述第一开关对组与第二开关对组间设有第一单极性电容,所述第二开关对组和第三开关对组件设有第二单极性电容；所述第一开关对组、第二开关对组和第三开关对组、第一单极性电容、第二单极性电容串联连接。该种基于混合开关的级联对称飞跨电容器式拓扑静态补偿器提高逆变器的效率,减少使用开关器件数量,损耗少并降低系统散热要求,同时保持系统的模块化和可扩展性。(The invention relates to a cascade symmetrical flying capacitor type topological static compensator based on a hybrid switch, which comprises symmetrical flying capacitor modules and a coupling inductor which are connected in series; the symmetrical flying capacitor module comprises three groups of module units which are connected in series; the module unit comprises a first switch pair group, a second switch pair group and a third switch pair group, wherein a first unipolar capacitor is arranged between the first switch pair group and the second switch pair group, and a second unipolar capacitor is arranged between the second switch pair group and the third switch pair group; the first switch pair group, the second switch pair group, the third switch pair group, the first unipolar capacitor and the second unipolar capacitor are connected in series. The cascade symmetrical flying capacitor type topology static compensator based on the hybrid switch improves the efficiency of an inverter, reduces the number of used switching devices, has low loss, reduces the system heat dissipation requirement, and simultaneously keeps the modularization and the expandability of the system.)

1. The cascade symmetrical flying capacitor type topological static compensator based on the hybrid switch is characterized by comprising symmetrical flying capacitor modules and a coupling inductor which are connected in series;

the symmetrical flying capacitor module comprises three groups of module units which are connected in series;

the module unit comprises a first switch pair group, a second switch pair group and a third switch pair group, wherein a first unipolar capacitor is arranged between the first switch pair group and the second switch pair group, and a second unipolar capacitor is arranged between the second switch pair group and the third switch pair group; the first switch pair group, the second switch pair group, the third switch pair group, the first unipolar capacitor and the second unipolar capacitor are connected in series;

the first switch pair group is an IGBT module, the second switch pair group is an IGCT module, and the third switch pair group is an IGBT module.

2. The cascaded symmetrical flying capacitor-based topological static compensator of claim 1, wherein a first unipolar capacitor and a second unipolar capacitor in three groups of modular units of the symmetrical flying capacitor are collectively referred to as C_mjWhere m e {1,2,3} represents the number of the module, j e {1,2} is the number of the capacitor in the module; the output voltage v of the symmetrical flying capacitor module_mThe dynamic properties of (A) are as shown in formula (1);

wherein, the S_jIs in the on-off state, V_CmjIs the capacitor voltage.

3. The hybrid switch-based cascaded symmetric flying capacitor topology static compensator of claim 2, wherein a voltage difference V between two switch pair groups_CmjAnd total output voltage level number N_levelsThe relationship between them is as shown in formula (2) and formula (3):

N_levels＝(2j+1)+4(m-1) (3)

switch S_m1,And S_m(j+1),Is equal to one dc voltage and the voltage stress on the intermediate pair of switches is equal to twice the dc voltage.

Technical Field

The invention belongs to the technical field of static compensators, and particularly relates to a cascade symmetrical flying capacitor type topological static compensator based on a hybrid switch.

Background

Static compensators based on multilevel inverters play a crucial role in controlling the grid voltage and regulating the grid reactive power. The quality of the output voltage of the inverter is closely related to the number of output levels of the inverter, and the output waveform is smoother due to the large number of levels, so that the electromagnetic interference can be effectively reduced, the harmonic content can be reduced, and the reliability of a system can be improved in practical application.

At present, a cascade multilevel topology structure is widely applied to a static compensator, but the structure needs to use a large number of switching devices, so that the complexity of system architecture and control is increased, and the system efficiency and reliability are affected. In order to reduce the number of switching appliances, the cascaded H-bridge multilevel topology structure uses less switching number than a neutral point clamping topology multilevel topology and a flying capacitor multilevel topology, and is emphasized, but when the cascaded H-bridge multilevel topology structure is applied to a three-phase system, the structure and the control are also complex; the modular design can improve the reliability of the system by arranging the redundant modules, and the system can still operate under the condition of partial module failure, so that the reliability of the power system is finally improved. The cascaded topology can be symmetrically or asymmetrically arranged according to the voltage, in most asymmetric structures, the power of different units is completely different, the power distribution is unbalanced due to asymmetric configuration, the module units are not easy to replace, and the mode has great limitation on a high-power application environment.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the defects, the invention provides the cascade symmetrical flying capacitor type topological static compensator based on the hybrid switch, which improves the efficiency of an inverter, reduces the number of used switching devices, has low loss, reduces the system heat dissipation requirement and simultaneously keeps the modularization and the expandability of the system.

The technical scheme adopted by the invention for solving the technical problems is as follows: the cascade symmetrical flying capacitor type topological static compensator based on the hybrid switch comprises symmetrical flying capacitor modules and a coupling inductor which are connected in series;

the symmetrical flying capacitor comprises three groups of module units which are connected in series;

the module unit comprises a first switch pair group, a second switch pair group and a third switch pair group, wherein a first unipolar capacitor is arranged between the first switch pair group and the second switch pair group, and a second unipolar capacitor is arranged between the second switch pair group and the third switch pair group; the first switch pair group, the second switch pair group, the third switch pair group, the first unipolar capacitor and the second unipolar capacitor are connected in series;

the first switch pair group is an IGBT module, the second switch pair group is an IGCT module, and the third switch pair group is an IGBT module.

Further, the first unipolar capacitor and the second unipolar capacitor in the three groups of module units of the symmetric flying capacitor are collectively referred to as C_mjWhere m e {1,2,3} represents the number of the module, j e {1,2} is the number of the capacitor in the module; the output voltage v of the symmetrical flying capacitor module_mThe dynamic properties of (A) are as shown in formula (1);

wherein, the S_jIs in the on-off state, V_CmjIs the capacitor voltage.

Further, the pressure difference V between two switch pair groups_CmjAnd total output voltage level number N_levelsThe relationship between them is as shown in formula (2) and formula (3):

N_levels＝(2j+1)+4(m-1) (3)

switch S_m1,And S_m(j+1),Is equal to one dc voltage and the voltage stress on the intermediate pair of switches is equal to twice the dc voltage.

The invention has the beneficial effects that: by adopting the scheme, the cascade symmetrical flying capacitor type topological static compensator based on the hybrid switch integrates a high-speed switch device (IGBT) and a high-voltage thyristor device (IGCT) into the static compensator module at the same time, so that the efficiency of the inverter is improved; the static compensator is in love with a die, can reduce the withstand voltage requirement of the inverter on a switch pair group, improves the quality of output current and voltage, can reduce the number of used switch devices, has less loss and reduces the heat dissipation requirement of a system, and simultaneously keeps the modularization and the expandability of the system.

The static compensator with the structure can enable the changed topological structure to be more suitable for the grid-connected application of industries (such as petroleum, natural gas, chemistry, metal, ships, mining and the like), traction, energy systems and high-power medium-voltage power grids, and has wide application range.

Drawings

The foregoing and other objects, features, and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of a topology circuit of a static compensator according to the present invention;

fig. 2 shows the operation mode of the switch in the static compensator according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, a cascaded symmetrical flying capacitor topology static compensator based on a hybrid switch includes a symmetrical flying capacitor module and a coupling inductor L connected in series;

the symmetrical flying capacitor module comprises three groups of module units which are connected in series;

the module unit comprises a first switch pair group, a second switch pair group and a third switch pair group, wherein a first unipolar capacitor is arranged between the first switch pair group and the second switch pair group, and a second unipolar capacitor is arranged between the second switch pair group and the third switch pair group; the first switch pair group, the second switch pair group, the third switch pair group, the first unipolar capacitor and the second unipolar capacitor are connected in series, the first switch pair group is an IGBT module, the second switch pair group is an IGCT module, and the third switch pair group is an IGBT module;

namely, the symmetric flying capacitor Module comprises a first Module unit Module 1, a second Module unit Module 2 and a third Module unit Module 3 which are sequentially connected in series; the first unipolar capacitor and the second unipolar capacitor in the three groups of module units are collectively called C_mjWhere m e {1,2,3} represents the number of the module, j e {1,2} is the number of the capacitor in the module; the output voltage v of the symmetrical flying capacitor module_mThe dynamic properties of (A) are as shown in formula (1);

wherein, the S_jIs in the on-off state, V_CmjIs the capacitor voltage; pressure difference V between two switch pair groups_CmjAnd total output voltage level number N_levelsThe relationship between them is as shown in formula (2) and formula (3):

N_levels＝(2j+1)+4(m-1) (3)

switch S_m1,And S_m(j+1),Is equal to one dc voltage and the voltage stress on the intermediate pair of switches is equal to twice the dc voltage, wherein the pattern of the pair of switches in the modular unit is shown in fig. 2.

In the cascade symmetrical flying capacitor type topology static compensator based on the hybrid switch, each module unit can generate five voltage levels, and three module units connected in series can generate 13 voltage levels when outputting, wherein different running states and conducting states of the switch in the static compensator are shown in table 1:

table 1: switch states of five-level SFC module

According to the cascade symmetrical flying capacitor type topological static compensator based on the hybrid switch, a high-speed switch device and a high-voltage thyristor-based device are simultaneously integrated in the static compensator module, so that the efficiency of an inverter is improved; the static compensator is modularized, the withstand voltage requirement of the inverter on a switch pair group can be reduced, the quality of output current and voltage is improved, the number of used switching devices can be reduced, the loss is low, the system heat dissipation requirement is reduced, and the modularization and the expandability of the system are kept.

In addition to the above embodiments, the present invention may further set the first switch pair group, the second switch pair group, and the third switch pair group as IGCT modules, so as to achieve the efficiency of the static compensator. In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.