Control method of multilevel converter and the multilevel converter

Patent metadata

Field	Value
Publication number	US-11245341-B2
Application number	US-202016802829-A
Country	US
Kind code	B2
Filing date	Feb 27, 2020
Priority date	Feb 28, 2019
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

A control method of a multilevel converter includes: classifying power modules that start working, need to update an output state or stop working to form m power module groups; and controlling power modules in a same one of the power module groups to start working, update the output state or stop working at the same time, and sequentially controlling the m power module groups to start working, or update the output state or stop working, according to a preset time interval. The number of power modules in each power module group is less than or equal to a preset value, causing a change value of an output level of the each power module group to be less than or equal to a preset voltage value.

First claim

What is claimed is:

1. A control method of a multilevel converter, the multilevel converter comprising n cascaded power modules and a processor coupled to the n cascaded power modules, and the control method comprising:
classifying at least two of the n cascaded power modules that start working, or need to update an output state, or stop working to form m power module groups, where n and m are integers and n>m>1; and
controlling every cascaded power module in a same one of them power module groups to start working, or update the output state, or stop working at the same time, and sequentially controlling the m power module groups to start working, or update the output state, or stop working, according to a preset time interval;
wherein the number of the at least two cascaded power modules in each of the m power module groups is less than or equal to a preset value, causing a change value of an output level of each of the m power module groups to be less than or equal to a preset voltage value,
wherein the output state comprises a zero level, a positive level, or a negative level, and
wherein the at least two of the n cascaded power modules that start working, or need to update an output state, or stop working are determined based on a working state of the multilevel converter, and the working state comprises a starting state, a running state, a first off state, or a second off state.

2. The control method according to claim 1 , further comprising:
determining that the working state is the first off state in response to a first off signal;
classifying the at least two of the n cascaded power modules that need to stop working to form the m power module groups; and
sequentially controlling, according to the preset time interval, the m power module groups to stop working.

3. The control method according to claim 2 , further comprising:
determining that the working state is the second off state in response to a second off signal; and
controlling every cascaded power module that has not stopped working to stop working immediately.

4. The control method according to claim 1 , further comprising:
determining that the working state is the second off state in response to a second off signal; and
controlling the n cascaded power modules to stop working immediately.

5. The control method according to claim 1 , further comprising:
classifying, when the working state is the starting state, the at least two of the n cascaded power modules to form the m power module groups; and
sequentially outputting, according to the preset time interval, control signals corresponding to each of the m power module groups, controlling every cascaded power module in a same one of the m power module groups to simultaneously enter the output state.

6. The control method according to claim 1 , further comprising:
comparing a current output state control signal with a previous output state control signal, when the working state is the running state;
classifying the at least two of the n cascaded power modules that need to update the output state to form the m power module groups; and
controlling every cascaded power module in a same one of the m power module groups to simultaneously update the output state, and sequentially controlling, according to the preset time interval, the m power module groups to update the output state.

7. The control method according to claim 1 , wherein the preset time interval is shorter than a switching period of a respective one of the n cascaded power modules.

8. The control method according to claim 1 , wherein the number of the at least two cascaded power modules in each of the m power module groups is the same.

9. The control method according to claim 1 , wherein the number of the at least two cascaded power modules in each of the m power module groups is different.

10. A multilevel converter, comprising:
n cascaded power modules; and
a processor coupled to the n cascaded power modules and configured to:
classify at least two of the n cascaded power modules that start working, or need to update an output state or stop working to form m power module groups, where n and m are integers and n>m>1; and
control every cascaded power module in a same one of the m power module groups to start working, or update the output state, or stop working at the same time, and sequentially control the m power module groups to start working, or update the output state, or stop working, according to a preset time interval;
wherein the number of the at least two cascaded power modules in each of the m power module groups is less than or equal to a preset value, causing a change value of an output level of each of the m power module groups to be less than or equal to a preset voltage value,
wherein the output state comprises a zero level, a positive level, or a negative level, and
wherein the at least two of the n cascaded power modules that start working, or need to update an output state, or stop working are determined based on a working state of the multilevel converter, and the working state comprises a starting state, a running state, a first off state, or a second off state.

11. The multilevel converter according to claim 10 , wherein the processor is configured to:
determine that the working state is the first off state in response to a first off signal;
classify the at least two of the n cascaded power modules that need to stop working to form the m power module groups; and
sequentially control, according to the preset time interval, the m power module groups to stop working.

12. The multilevel converter according to claim 11 , wherein the processor is configured to:
determine that the working state is the second off state in response to a second off signal; and
control every cascaded power module that has not stopped working to stop working immediately.

13. The multilevel converter according to claim 10 , wherein the processor is configured to:
determine that the working state is the second off state in response to a second off signal; and
control the n cascaded power modules to stop working immediately.

14. The multilevel converter according to claim 10 , wherein the processor is configured to:
classify, when the working state is the starting state, the at least two of the n cascaded power modules to form the m power module groups; and
sequentially output, according to the preset time interval, control signals corresponding to each of the m power module groups, controlling every cascaded power module in a same one of the m power module groups to enter the output state at the same time.

15. The multilevel converter according to claim 10 , wherein the processor is configured to:
compare a current output state control signal with a previous output state control signal, when the working state is the running state;
classify the at least two of the n cascaded power modules that need to update the output state to form the m power module groups; and
control every cascaded module in a same one of the m power module groups to update the output state at the same time, and sequentially control, according to the preset time interval, the m power module groups to update the output state.

16. The multilevel converter according to claim 10 , wherein the preset time interval is shorter than a switching period of a respective one of the n cascaded power modules.

17. The multilevel converter according to claim 10 , wherein the number of the at least two cascaded power modules in each of the m power module groups is the same.

18. The multil

Assignees

• Delta Electronics Shanghai Co

Inventors

• Ying Jianping
• Xie Wei
• Wei Lan
• Zheng Jianfei
• Liu Bingjie
• Shen Dingkun
• Hu Zhiming
• Xu Wei
• Liu Yang

Classifications

• H02M7/483 Primary

  Converters with outputs that each can have more than two voltages levels · CPC title

• H02M7/4835

  comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage · CPC title

• H02M1/088

  for the simultaneous control of series or parallel connected semiconductor devices · CPC title

• H02M1/0003

  Details of control, feedback or regulation circuits · CPC title