Power electronic transformer system, transformer and fault ride-through control method thereof

Abstract

The invention relates to a power electronic transformer system, a transformer and a fault ride-through control method thereof, belonging to the technical field of bidirectional isolated DC voltage conversion. The power electronic transformer includes at least one module group. Each module group includes a high-voltage half-bridge module and a bidirectional DC conversion unit. Each high-voltage half-bridge module includes a high-voltage upper arm branch and a high-voltage lower arm branch. The power electronic transformer also includes a self-blocking module which is connected in parallel withthe low-voltage side of each module group. The self-blocking module includes low-voltage half-bridge modules. Each low-voltage half-bridge module includes a low-voltage upper arm branch and a low-voltage lower arm branch. The low-voltage lower arm branches are used to connect a DC power grid at the low-voltage side. The main branch formed by connecting the low-voltage upper arm branches and the low-voltage lower arm branches is connected in parallel with the low-voltage side of each module group. Through cooperative control of the half-bridge modules arranged at the high-voltage sides of the module groups and the half-bridge modules in the self-blocking module, the power electronic transformer of the invention has the fault ride-through ability, and the operation reliability and stabilityof the power grid are improved.

Description

technical field [0001] The invention belongs to the technical field of bidirectional isolated DC voltage conversion, and in particular relates to a power electronic transformer system, a transformer and a fault ride-through control method thereof. Background technique [0002] At present, power electronic transformers used in DC distribution network, new energy grid connection and energy Internet have many advantages, such as: reduced weight and volume; precise and controllable voltage and current, improved power quality; modular design, easy for system expansion, Disassembly and maintenance; it has the advantages of low pollution, high efficiency and intelligence. However, when the power electronic transformer fails, the entire system where the power electronic transformer is located will fail and shut down, which will seriously affect the reliability and stability of the DC distribution network power supply. Contents of the invention [0003] The purpose of the present ...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a power electronic transformer, which is used to solve the problem of providing execution hardware for the power electronic transformer with fault ride-through capability;

[0004] A fault ride-through control method for power electronic transformers is also proposed, which is used to solve the problem that when a short-circuit fault occurs in the DC power grid on the high-voltage side (referring to the DC power grid connected to the high-voltage side of the power electronic transformer), the power electronic transformer in the prior art fails and the system shuts down. Causes the problem of reduced reliability and stability of power grid operation;

[0005] And another fault ride-through control method for power electronic transformers, which is used to solve the problem that when a short-circuit fault occurs in the low-voltage side DC power grid (referring to the DC power grid connected to the low-voltage side of the power electronic transformer), the power electronic transformer in the prior art fails, that is, the system shuts down, Causes the problem of reduced reliability and stability of power grid operation;

[0006] A power electronic transformer system is also proposed, which is used to solve the problem that the power electronic transformer in the prior art fails, that is, the system shuts down, which causes the reliability and stability of the power grid to decrease.

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