A method for assessing failure rate of mmc

Abstract

The invention discloses a fault rate evaluation method of an MMC (Modular Multilevel Converter). The fault rate evaluation method comprises the following steps: (1) acquiring a sub-module and a sub-module assembly of an MMC circuit; (2) inputting working parameters of the MMC circuit and the sub-module assembly thereof, and finishing setting of initial conditions; (3) calculating a fault rate of the sub-module assembly according to a fault model to obtain the fault rate of the sub-module; (4) establishing a Markov model of the MMC circuit and establishing a state transfer equation based on the Markov model; (5) solving the state transfer equation to obtain a variation function of the fault rate of the MMC circuit along with time and module quantity, a variation function of the reliability along with the time and the module quantity and average failure time. The calculation reliability of the fault rate of the sub-module assembly is greatly improved and the estimation reliability of the fault rate of the MMC circuit is improved; by applying the Markov model, the solved fault rate and average service life of the MMC circuit are relatively accurate and are varied along with time variation; the fault rate evaluation method has a dynamic property and high fault evaluation precision.

Description

technical field

[0001] The invention relates to a failure rate evaluation method, in particular to an MMC failure rate evaluation method, and belongs to the field of power system reliability evaluation. Background technique

[0002] Modular Multilevel Converter (MMC), since it was proposed by German scholar R. Marquardt in 2002, has been widely concerned and researched by scholars from various countries because of its unique advantages in high-voltage and high-power applications. Mainly concentrated in the fields of HVDC, power quality control and AC drive, especially the primary choice of HVDC converters.

[0003] There are multiple sub-modules in the modular multi-level converter MMC. The reliability of the sub-modules greatly affects the overall reliability of the MMC. The failure of a sub-module will affect the normal operation of the MMC converter. Therefore, it is necessary to study the failure rate of the MMC. necessary.

[0004] In the traditional failure rate eval...

Examples

Embodiment Construction

[0040] Below in conjunction with accompanying drawing of description, the present invention will be further described.

[0041] The invention provides a failure rate evaluation method of MMC, such as figure 1 shown, including the following steps:

[0042] 1) Obtain the submodule and submodule assembly of the MMC circuit;

[0043] Such as figure 2 Shown is the MMC circuit topology diagram, in which each box represents a sub-module, the sub-module adopts the structure of a half-bridge sub-module, and the sub-module components in each sub-module include IGBT, capacitor and diode.

[0044] The main cause of sub-module failure is the damage of power electronic devices. The overload capacity of power electronic devices such as IGBT and diodes is weak. Overvoltage, overcurrent or excessive voltage and current rise rate may cause damage to power electronic devices, and capacitor Damage and trigger control failure etc. The failure of the sub-module will cause the oscillation of DC...

technical field

[0001] The invention relates to a failure rate evaluation method, in particular to an MMC failure rate evaluation method, and belongs to the field of power system reliability evaluation. Background technique

[0002] Modular Multilevel Converter (MMC), since it was proposed by German scholar R. Marquardt in 2002, has been widely concerned and researched by scholars from various countries because of its unique advantages in high-voltage and high-power applications. Mainly concentrated in the fields of HVDC, power quality control and AC drive, especially the primary choice of HVDC converters.

[0003] There are multiple sub-modules in the modular multi-level converter MMC. The reliability of the sub-modules greatly affects the overall reliability of the MMC. The failure of a sub-module will affect the normal operation of the MMC converter. Therefore, it is necessary to study the failure rate of the MMC. necessary.

[0004] In the traditional failure rate eval...

Examples

Embodiment Construction

[0040] Below in conjunction with accompanying drawing of description, the present invention will be further described.

[0041] The invention provides a failure rate evaluation method of MMC, such as figure 1 shown, including the following steps:

[0042] 1) Obtain the submodule and submodule assembly of the MMC circuit;

[0043] Such as figure 2 Shown is the MMC circuit topology diagram, in which each box represents a sub-module, the sub-module adopts the structure of a half-bridge sub-module, and the sub-module components in each sub-module include IGBT, capacitor and diode.

[0044] The main cause of sub-module failure is the damage of power electronic devices. The overload capacity of power electronic devices such as IGBT and diodes is weak. Overvoltage, overcurrent or excessive voltage and current rise rate may cause damage to power electronic devices, and capacitor Damage and trigger control failure etc. The failure of the sub-module will cause the oscillation of DC...

Images