半桥和全桥子模块混合型换流器的充电策略

Charging Strategies for Hybrid Converters Based on Half-bridge Sub-module and Full-bridge Sub-module

介绍了半桥和全桥子模块混合型模块化多电平换流器在不控充电阶段的充电模态和充电电压,分析了该换流器在不控充电阶段半桥子模块存在自取能不成功的问题。为此,提出了三段式充电策略,将充电过程分为不控充电、半控充电模式1和半控充电模式2这三个阶段,半控充电模式1阶段所有全桥子模块旁路,半控充电模式2阶段所有全桥子模块半闭锁。分析了半控充电模式1和半控充电模式2的充电模态和充电电压,并通过仿真对所提三段式充电策略进行了验证。理论分析和仿真结果表明,所提三段式充电策略可以解决半桥子模块自取能不成功的问题。

The charging mode and charging voltage on uncontrolled charging stage of hybrid modular multilevel converter based on half-bridge sub module and full-bridge sub-module are introduced. The problem of unsuccessful self taking energy by half- bridge sub modules of the hybrid converter on the uncontrolled charging stage is analyzed. The three stage charging strategies are proposed to solve the problem mentioned above, and the charging process is divided into three stages, which are called uncontrolled charging, half controlled charging mode 1 and 2. On the stage 1 of half controlled charging mode, all the full- bridge sub-modules are bypassed. On the stage 2 of half controlled charging mode, all the full-bridge sub-modules are partly blocked. The charging modes and charging voltages of half controlled charging mode 1 and mode 2 are analyzed. The three stage charging strategies are verified by simulations. The theoretical analysis and simulation results show that the proposed three stage charging strategies can solve the problem of unsuccessful self taking energy by half-bridge sub-modules of the hybrid converter.