WO2023142263A1 - Multi-level converter and multi-level converter system - Google Patents

Abstract

A multi-level converter and a multi-level converter system. Compared with an existing multi-level converter, only ten controllable switches are used for the multi-level converter, and the voltage stress borne by each switch is equal, so that the complexity of a topological structure is reduced, and the reliability and efficiency of the multi-level converter are improved.

Description

A kind of multilevel converter and multilevel converter system

This application claims the priority of the Chinese patent application with the application number 202210101679.8 and the title of the invention "a multi-level converter and multi-level converter system" submitted to the China Patent Office on January 27, 2022. The entire contents are incorporated by reference in this application.

technical field

The invention relates to the technical field of power electronics, in particular to a multilevel converter and a multilevel converter system.

Background technique

At present, with the development of science and technology, the demand for multilevel converters is also increasing. Compared with traditional two-level converters, multilevel converters can obtain high-quality output waveforms At the same time, it also overcomes many shortcomings of traditional two-level converters, such as multi-level converters do not need output transformers and dynamic voltage equalization circuits, low switching frequency, small voltage stress of switching devices, high system efficiency, and little pollution to the grid. .

In the prior art, as shown in Fig. 1, Fig. 1 is a common multilevel converter in the prior art. It can be seen from the figure that the multilevel converter uses twelve controllable switches. By controlling these Twelve controllable switches are turned on or off, and five different levels of voltage can be obtained: -U, -U/2, 0, U/2, U. This multi-level converter consists of a three-level converter Level active clamp converter and a two-stage converter are composed of two parts of the circuit. In order to ensure that all switches bear the same voltage stress, this multi-level converter needs to consider the voltage and current distribution of the two parts of the circuit. , thus increasing the complexity of the circuit design and reducing the reliability of the multilevel converter.

Contents of the invention

The purpose of the present invention is to provide a multi-level converter and a multi-level converter system, only ten controllable switches are used, and the voltage stress of each switch is equal, reducing the complexity of the converter topology To improve the reliability and efficiency of the multilevel converter.

In order to solve the above technical problems, the present invention provides a multilevel converter, including a first controllable switch, a second controllable switch, a third controllable switch, a fourth controllable switch, a fifth controllable switch, The sixth controllable switch, the seventh controllable switch, the eighth controllable switch, the ninth controllable switch, the tenth controllable switch, the first capacitor, the second capacitor, the third capacitor and the fourth capacitor;

The first capacitor, the second capacitor and the third capacitor are connected in series with both ends of the DC power supply in sequence, and the first controllable switch and the second controllable switch are connected in parallel with the first capacitor after being connected in series, so The third controllable switch and the fourth controllable switch are connected in parallel to the third capacitor after being connected in series, and the common terminal connected between the first controllable switch and the second controllable switch is connected to the fifth controllable switch The first end of the switch is connected, the second end of the fifth controllable switch is respectively connected with the first end of the seventh controllable switch and the first end of the ninth controllable switch, and the third controllable switch The common terminal connected between the control switch and the fourth controllable switch is connected to the first terminal of the sixth controllable switch, and the second terminal of the sixth controllable switch is respectively connected to the first terminal of the eighth controllable switch. The two terminals are connected to the second terminal of the tenth controllable switch, the second terminal of the seventh controllable switch is connected to the first terminal of the eighth controllable switch and the connected common terminal is connected to one terminal of the load , the second end of the ninth controllable switch is connected to the first end of the tenth controllable switch and the connected common end is connected to the other end of the load, the first end of the fourth capacitor is connected to the first end of the connected to the second end of the fifth controllable switch, and the second end of the fourth capacitor is connected to the second end of the sixth controllable switch.

Preferably, it also includes:

A filtering module whose input terminals are respectively connected to the common terminal connected to the seventh controllable switch and the eighth controllable switch and the common terminal connected to the ninth controllable switch and the tenth controllable switch, the said The output end of the filter module is connected to the load for filtering.

Preferably, the filter module includes a filter inductor and a filter capacitor, the first end of the filter inductor is connected to the common end of the seventh controllable switch and the eighth controllable switch, and the first end of the filter inductor The two ends are connected to the first end of the filter capacitor, the second end of the filter capacitor is connected to the common end connected between the ninth controllable switch and the tenth controllable switch, and the two ends of the filter capacitor Also connected to the load.

Preferably, the filter module includes a first filter inductor, a second filter inductor and a filter capacitor, the first end of the first filter inductor is connected to the common connection between the seventh controllable switch and the eighth controllable switch The second end of the first filter inductor is connected to the first end of the second filter inductor, the common end of the connection is connected to the first end of the filter capacitor, and the second end of the filter capacitor It is connected to the common end connected to the ninth controllable switch and the tenth controllable switch, the second end of the second filter inductor is connected to one end of the load, the second end of the filter capacitor is connected to the Connect to the other end of the load.

Preferably, the first controllable switch, the second controllable switch, the third controllable switch, the fourth controllable switch, the fifth controllable switch, the sixth controllable switch . The seventh controllable switch, the eighth controllable switch, the ninth controllable switch and the tenth controllable switch are all IGBT tubes.

In order to solve the above technical problems, the present invention also provides a multilevel converter system, including the multilevel converter as described above, and also includes a switch control module, the switch control module is connected to the first The control terminal of the first controllable switch, the control terminal of the second controllable switch, the control terminal of the third controllable switch, the control terminal of the fourth controllable switch, the control terminal of the fifth controllable switch, the control terminal of the sixth controllable switch The control terminal, the control terminal of the seventh controllable switch, the control terminal of the eighth controllable switch, the control terminal of the ninth controllable switch, and the control terminal of the tenth controllable switch are connected, and the switch control module is used to generate switch drive signal to control the turn-on and turn-off of each controllable switch.

The invention provides a multi-level converter and a multi-level converter system. Compared with the existing multi-level converter, the multi-level converter provided by the invention only uses ten control switches, and each switch bears the same voltage stress, which reduces the complexity of the topology and improves the reliability and efficiency of the multilevel converter.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the prior art and the accompanying drawings that need to be used in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a multilevel converter in the prior art;

Fig. 2 is a schematic structural diagram of a multilevel converter provided by the present invention.

Detailed ways

The core of the present invention is to provide an inverter DC bus voltage setting method and related components, which can improve the overall conversion efficiency of the inverter and improve the performance of the inverter.

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to Fig. 2. Fig. 2 is a schematic structural diagram of a multilevel converter provided by the present invention, including a first controllable switch S1, a second controllable switch S2, a third controllable switch S3, a fourth controllable switch Switch S4, fifth controllable switch S5, sixth controllable switch S6, seventh controllable switch S7, eighth controllable switch S8, ninth controllable switch S9, tenth controllable switch S10, first capacitor C1, the second capacitor C2, the third capacitor C3 and the fourth capacitor C4;

The first capacitor C1, the second capacitor C2, and the third capacitor C3 are sequentially connected in series to both ends of the DC power supply, the first controllable switch S1 and the second controllable switch S2 are connected in parallel to the first capacitor C1, and the third controllable switch S2 is connected in parallel to the first capacitor C1. The control switch S3 and the fourth controllable switch S4 are connected in parallel with the third capacitor C3 after being connected in series, the common end connected between the first controllable switch S1 and the second controllable switch S2 is connected to the first end of the fifth controllable switch S5, and the first end of the fifth controllable switch S5 is connected. The second end of the fifth controllable switch S5 is respectively connected to the first end of the seventh controllable switch S7 and the first end of the ninth controllable switch S9, and the third controllable switch S3 is connected to the fourth controllable switch S4. end is connected with the first end of the sixth controllable switch S6, the second end of the sixth controllable switch S6 is respectively connected with the second end of the eighth controllable switch S8 and the second end of the tenth controllable switch S10, the second end of the sixth controllable switch S6 The second end of the seventh controllable switch S7 is connected to the first end of the eighth controllable switch S8 and the connected common end is connected to one end of the load, the second end of the ninth controllable switch S9 is connected to the first end of the tenth controllable switch S10 The first end is connected and the connected common end is connected to the other end of the load, the first end of the fourth capacitor C4 is connected to the second end of the fifth controllable switch S5, and the second end of the fourth capacitor C4 is connected to the sixth controllable switch S5. The second end of the switch S6 is connected.

At present, a common multilevel converter in the prior art is shown in Figure 1, and Figure 1 is a five-level active clamp converter in the prior art, it can be seen that this multilevel converter The converter needs twelve controllable switches, and five different levels of voltage can be obtained by controlling the on and off of the twelve controllable switches: -U, -U/2, 0, U/2, U. Specifically, this converter is composed of a three-level active clamp converter and a two-level converter. In actual use, it is necessary to consider the voltage and current distribution of these two parts of the circuit, increasing the It increases the topology complexity of the circuit and reduces the reliability of the system.

In order to solve the above problems, the multilevel converter provided in this embodiment reduces the number of controllable switches to ten. At the same time, since three DC capacitors C1, C2, C3 and one flying capacitor C4 are set, ten The voltage of each controllable switch is equally divided, which ensures that the voltage stress of each switch is equal, and increases the reliability of the converter.

In addition, in addition to ensuring the balance of the circuit, the flying capacitor C4 here is in a process of charging and discharging during the operation of the converter, so as to ensure that the current in the circuit will not change suddenly and play a role in continuous flow. effect.

It should also be noted that the multilevel converter provided by the present invention can output seven different level voltages by controlling the on and off of ten controllable switches. In order to be able to output seven kinds of level voltages, this The working state of the controllable switch of the multilevel converter provided by the invention should follow the following guidelines:

The first controllable switch S1 and the second controllable switch S2, the third controllable switch S3 and the fourth controllable switch S4, the fifth controllable switch S5 and the sixth controllable switch S6, the seventh controllable switch S7 and the fourth controllable switch The eighth controllable switch S8 , the ninth controllable switch S9 and the tenth controllable switch S10 should be turned on or off in a complementary manner, for example, when S1 is turned on, S2 is turned off.

The first controllable switch S1 and the third controllable switch S3, the second controllable switch S2 and the fourth controllable switch S4 should be turned on or turned off at the same time.

It should be noted that, under the normal operation of the multilevel converter provided by the present invention, the first controllable switch S1 and the fourth controllable switch S4 should not be turned on at the same time, but if in other usage scenarios, the first controllable switch When the switch S1 and the fourth controllable switch S4 are turned on at the same time, it should be ensured that the fifth controllable switch S5 and the sixth controllable switch S6 can withstand the voltage stress of 2Vdc/3, so as to ensure the reliability of the whole system.

Specifically, according to the controllable switch turn-on or turn-off criterion of the above-mentioned multilevel converter, there are 16 different switch states, which can output voltages of seven different levels: 0, Vdc/3, -Vdc/3 , 2Vdc/3, -2Vdc/3, Vdc, -Vdc. Please refer to Table 1, Table 1 is a working state table of a controllable switch of a multilevel converter provided by the present invention.

Table 1

S1	S5	S7	S9	phase voltage	switch status
0	0	0	0	0	V1
0	0	0	1	0	V2
0	0	1	0	V dc /3	V3
0	0	1	1	-V dc /3	V4
0	1	0	0	V dc /3	V5
0	1	0	1	-V dc /3	V6
1	0	0	0	V dc /3	V7
1	0	0	1	-V dc /3	V8
0	1	1	0	2V dc /3	V9
0	1	1	1	-2V dc /3	V10
1	0	1	0	2V dc /3	V11
1	0	1	1	-2V dc /3	V12
1	1	0	0	2V dc /3	V13
1	1	0	1	-2V dc /3	V14
1	1	1	0	V dc	V15
1	1	1	1	-V dc	V16

Switch state 1: The second controllable switch S2, the fourth controllable switch S4, the sixth controllable switch S6, the eighth controllable switch S8, and the tenth controllable switch S10 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the fifth control switch S5, the seventh control switch S7, and the ninth control switch S9 are turned off.

Switch state 2: The second controllable switch S2, the fourth controllable switch S4, the sixth controllable switch S6, the eighth controllable switch S8, and the ninth controllable switch S9 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the fifth control switch S5, the seventh control switch S7, and the tenth control switch S10 are turned off.

Switch state 3: the second controllable switch S2, the fourth controllable switch S4, the sixth controllable switch S6, the seventh controllable switch S7, the tenth controllable switch S10 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the fifth control switch S5, the eighth control switch S8, and the ninth control switch S9 are turned off.

Switch state 4: The second controllable switch S2, the fourth controllable switch S4, the sixth controllable switch S6, the seventh controllable switch S7, and the ninth controllable switch S9 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the fifth control switch S5, the eighth control switch S8, and the tenth control switch S10 are turned off.

Switch state 5: The second controllable switch S2, the fourth controllable switch S4, the fifth controllable switch S5, the eighth controllable switch S8, and the tenth controllable switch S10 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the sixth control switch S6, the seventh control switch S7, and the ninth control switch S9 are turned off.

Switch state 6: The second controllable switch S2, the fourth controllable switch S4, the fifth controllable switch S5, the eighth controllable switch S8, and the ninth controllable switch S9 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the sixth control switch S6, the seventh control switch S7, and the tenth control switch S10 are turned off.

Switch state 7: the first controllable switch S1, the third controllable switch S3, the sixth controllable switch S6, the eighth controllable switch S8, the tenth controllable switch S10 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the fifth control switch S5, the seventh control switch S7, and the ninth control switch S9 are turned off.

Switch state 8: The first controllable switch S1, the third controllable switch S3, the sixth controllable switch S6, the eighth controllable switch S8, and the ninth controllable switch S9 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the fifth control switch S5, the seventh control switch S7, and the tenth control switch S10 are turned off.

Switch state 9: The second controllable switch S2, the fourth controllable switch S4, the fifth controllable switch S5, the seventh controllable switch S7, and the tenth controllable switch S10 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the sixth control switch S6, the eighth control switch S8, and the ninth control switch S9 are turned off.

Switch state 10: The second controllable switch S2, the fourth controllable switch S4, the fifth controllable switch S5, the seventh controllable switch S7, and the ninth controllable switch S9 are turned on, the first controllable switch S1, the third controllable switch The control switch S3, the sixth control switch S6, the eighth control switch S8, and the tenth control switch S10 are turned off.

Switch state 11: the first controllable switch S1, the third controllable switch S3, the sixth controllable switch S6, the seventh controllable switch S7, the tenth controllable switch S10 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the fifth control switch S5, the eighth control switch S8, and the ninth control switch S9 are turned off.

Switch state 12: the first controllable switch S1, the third controllable switch S3, the sixth controllable switch S6, the seventh controllable switch S7, the ninth controllable switch S9 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the fifth control switch S5, the eighth control switch S8, and the tenth control switch S10 are turned off.

Switch state 13: the first controllable switch S1, the third controllable switch S3, the fifth controllable switch S5, the eighth controllable switch S8, the tenth controllable switch S10 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the sixth control switch S6, the seventh control switch S7, and the ninth control switch S9 are turned off.

Switch state 14: the first controllable switch S1, the third controllable switch S3, the fifth controllable switch S5, the eighth controllable switch S8, and the ninth controllable switch S9 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the sixth control switch S6, the seventh control switch S7, and the tenth control switch S10 are turned off.

Switch state 15: the first controllable switch S1, the third controllable switch S3, the fifth controllable switch S5, the seventh controllable switch S7, the tenth controllable switch S10 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the sixth control switch S6, the eighth control switch S8, and the ninth control switch S9 are turned off.

Switch state 16: the first controllable switch S1, the third controllable switch S3, the fifth controllable switch S5, the seventh controllable switch S7, and the ninth controllable switch S9 are turned on, the second controllable switch S2, the fourth controllable switch The control switch S4, the sixth control switch S6, the eighth control switch S8, and the tenth control switch S10 are turned off.

To sum up, the present invention provides a multilevel converter. Compared with the existing multilevel converter, the multilevel converter provided by the present invention only uses ten controllable switches, and each The voltage stress of each switch is equal, which reduces the complexity of the topology and improves the reliability and efficiency of the multilevel converter.

On the basis of above-mentioned embodiment:

As a preferred embodiment, it also includes:

The input end is respectively connected to the common end connected to the seventh controllable switch and the eighth controllable switch and the common end connected to the ninth controllable switch and the tenth controllable switch. for filtering.

In this embodiment, considering that the voltage available for the load to work normally should be a sine wave voltage, this solution also adds a filter module, the first input terminal of the filter module is connected to the seventh controllable switch and the eighth controllable switch The common terminal is connected, the input terminal of the second terminal of the filter module is connected to the common terminal connected to the ninth controllable switch and the tenth controllable switch, and the output terminal is connected to the load. It is used to filter the pulse output by the converter and convert it into a sine wave voltage for the load to work normally, increasing the reliability of the converter.

As a preferred embodiment, the filter module includes a filter inductor and a filter capacitor, the first end of the filter inductor is connected to the common end of the seventh controllable switch and the eighth controllable switch, and the second end of the filter inductor is connected to the filter capacitor The second end of the filter capacitor is connected to the common end connected to the ninth controllable switch and the tenth controllable switch, and the two ends of the filter capacitor are also connected to the load.

In this embodiment, the filter module uses an LC filter circuit, which is easy to implement and increases the feasibility of the solution.

As a preferred embodiment, the filter module includes a first filter inductor, a second filter inductor and a filter capacitor, the first end of the first filter inductor is connected to the common end of the seventh controllable switch and the eighth controllable switch, The second end of the first filter inductance is connected to the first end of the second filter inductance, the common end connected to it is connected to the first end of the filter capacitor, and the second end of the filter capacitor is connected to the ninth controllable switch and the tenth controllable switch. The common end of the switch connection is connected, the second end of the second filter inductor is connected to one end of the load, and the second end of the filter capacitor is connected to the other end of the load.

In this embodiment, the filter module uses an LCL filter circuit, which is easy to implement and increases the feasibility of the solution.

As a preferred embodiment, the first controllable switch, the second controllable switch, the third controllable switch, the fourth controllable switch, the fifth controllable switch, the sixth controllable switch, the seventh controllable switch, The eighth controllable switch, the ninth controllable switch and the tenth controllable switch are all IGBT tubes.

In this embodiment, the IGBT tube is used as the controllable switch in the multilevel converter of the present invention. The IGBT tube has the characteristics of high input impedance, low voltage control power consumption, high voltage resistance, and large current, and is more suitable for application in a multilevel converter.

The present invention also provides a multilevel converter system, including the above multilevel converter, and also includes a switch control module, the switch control module is connected with the control terminal of the first controllable switch S1 and the second controllable switch S1 respectively. The control terminal of the control switch S2, the control terminal of the third controllable switch S3, the control terminal of the fourth controllable switch S4, the control terminal of the fifth controllable switch S5, the control terminal of the sixth controllable switch S6, the control terminal of the seventh controllable switch The control terminal of the control switch S7, the control terminal of the eighth controllable switch S8, the control terminal of the ninth controllable switch S9, and the control terminal of the tenth controllable switch S10 are connected, and the switch control module is used to generate a switch drive signal to control Turn on and off of each controllable switch.

For the introduction of a multi-level converter system provided by the present invention, please refer to the above device embodiment, and the present invention will not be repeated here.

It should also be noted that in this specification, relative terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations There is no such actual relationship or order between the operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A multilevel converter, characterized by comprising a first controllable switch, a second controllable switch, a third controllable switch, a fourth controllable switch, a fifth controllable switch, a sixth controllable switch, The seventh controllable switch, the eighth controllable switch, the ninth controllable switch, the tenth controllable switch, the first capacitor, the second capacitor, the third capacitor and the fourth capacitor;

   The first capacitor, the second capacitor and the third capacitor are connected in series with both ends of the DC power supply in sequence, and the first controllable switch and the second controllable switch are connected in parallel with the first capacitor after being connected in series, so The third controllable switch and the fourth controllable switch are connected in parallel to the third capacitor after being connected in series, and the common terminal connected between the first controllable switch and the second controllable switch is connected to the fifth controllable switch The first end of the switch is connected, the second end of the fifth controllable switch is respectively connected with the first end of the seventh controllable switch and the first end of the ninth controllable switch, and the third controllable switch The common terminal connected between the control switch and the fourth controllable switch is connected to the first terminal of the sixth controllable switch, and the second terminal of the sixth controllable switch is respectively connected to the first terminal of the eighth controllable switch. The two terminals are connected to the second terminal of the tenth controllable switch, the second terminal of the seventh controllable switch is connected to the first terminal of the eighth controllable switch and the connected common terminal is connected to one terminal of the load , the second end of the ninth controllable switch is connected to the first end of the tenth controllable switch and the connected common end is connected to the other end of the load, the first end of the fourth capacitor is connected to the first end of the connected to the second end of the fifth controllable switch, and the second end of the fourth capacitor is connected to the second end of the sixth controllable switch.
2. The multilevel converter according to claim 1, further comprising:

   A filtering module whose input terminals are respectively connected to the common terminal connected to the seventh controllable switch and the eighth controllable switch and the common terminal connected to the ninth controllable switch and the tenth controllable switch, the said The output end of the filter module is connected to the load for filtering.
3. The multilevel converter according to claim 2, wherein the filter module includes a filter inductor and a filter capacitor, and the first end of the filter inductor is connected to the seventh controllable switch and the eighth controllable switch. The common end connected to the controllable switch is connected, the second end of the filter inductor is connected to the first end of the filter capacitor, and the second end of the filter capacitor is connected to the ninth controllable switch and the tenth controllable switch. The common terminal connected to the control switch is connected, and the two ends of the filter capacitor are also connected to the load.
4. The multilevel converter according to claim 2, wherein the filter module includes a first filter inductor, a second filter inductor, and a filter capacitor, and the first end of the first filter inductor is connected to the first filter inductor. The seven controllable switches are connected to the common end connected to the eighth controllable switch, the second end of the first filter inductor is connected to the first end of the second filter inductor, and the common end connected to the filter inductor is connected to the filter The first end of the capacitor is connected, the second end of the filter capacitor is connected to the common end of the ninth controllable switch and the tenth controllable switch, the second end of the second filter inductor is connected to the One end of the load is connected, and the second end of the filter capacitor is connected to the other end of the load.
5. The multilevel converter according to any one of claims 1 to 4, wherein the first controllable switch, the second controllable switch, the third controllable switch, the first Four controllable switches, the fifth controllable switch, the sixth controllable switch, the seventh controllable switch, the eighth controllable switch, the ninth controllable switch and the tenth controllable switch The control switches are all IGBT tubes.
6. A multilevel converter system, characterized in that it includes the multilevel converter according to any one of claims 1 to 5, and further includes a switch control module, the switch control module is connected to the first The control terminal of the first controllable switch, the control terminal of the second controllable switch, the control terminal of the third controllable switch, the control terminal of the fourth controllable switch, the control terminal of the fifth controllable switch, the control terminal of the sixth controllable switch The control terminal, the control terminal of the seventh controllable switch, the control terminal of the eighth controllable switch, the control terminal of the ninth controllable switch, and the control terminal of the tenth controllable switch are connected, and the switch control module is used to generate switch drive signal to control the turn-on and turn-off of each controllable switch.

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