应用于配电物联网的高压直流固态变压器启动策略研究

直流固态变压器作为未来能源互联网的关键智能装备之一,在配电物联网中具有广阔的应用前景。然而,在其启动过程中往往会造成很大的冲击电流,对配电系统稳定性造成了影响。文章提出了一种有效的一次侧/二次侧子模块软充电策略,一次侧充电策略采用不控充电阶段和最大电流可控充电阶段以控制桥臂充电电流峰值。二次侧充电策略采用定占空比增大法,使得交流侧充电电流逐渐增大至稳态。该方法不需要借助额外的辅助电源,通过子模块的投入与闭锁状态,将各子模块充电至一定电压,抑制充电电流尖峰。文章分析了各个充电状态下的功率传导公式,得出了二次侧的最大充电电压。最后通过Matlab仿真,验证了该方法的有效性。

Research on Start-up Strategy of HVDC Solid-state Transformer Applied to Distribution Internet of Things

As one of the key intelligent equipments of the future energy Internet,DC solid-state transformer has a broad application prospect in the distribution Internet of Things. However,it often causes a large impluse current in the process of start-up,which has an impact on the stability of the power distribution system. In this paper,an effective primary/secondary sub-module soft charging strategy was proposed. The primary-side charging strategy was divided into an uncontrolled charging stage and a maximum current controllable charging stage to control the peak charging current of the bridge arm. The secondaryside charging strategy adopted the method of increasing the constant duty cycle,which makes the charging current at the AC side gradually increase to the steady state. There is no need to use additional auxiliary power supply. Through the charging and blocking state of the sub-modules,the sub-module were charged to a certain voltage to suppress the peak of charging current. In this paper,the formula of power conduction under different charging states was analyzed,and the maximum charging voltage of the secondary side was obtained. Finally,the validity of this method was verified by MATLAB simulation.