电流外环电压内环无缝切换控制策略

Control Strategy for Seamless Switch of Outer Current and Inner Voltage

逆变器在独立/并网模式切换瞬间容易出现过电压和过电流问题。为此,本文提出电流外环、电压内环的控制策略,保证模式切换时控制指令的稳定性;同时为了减小控制误差引入前馈控制,最终达到减小系统的过渡时间和改善供电电压质量的目的。为验证此控制策略的有效性,本文利用电磁暂态仿真软件PSCAD/EMTDC建立双模式供电系统模型,对所提切换控制策略与传统模式切换进行了仿真比较。仿真结果表明,所提出的切换控制策略能有效抑制独立/并网模式相互切换引起的暂态冲击,达到无缝切换的目的。

Overvoltage usually occurs when an inverter switches between stand-alone and grid-connected modes. Thispaper presents a control strategy for outer current and inner voltage to ensure the stability of switching control instruction. At the same time,feed-forward control is introduced to reduce control error,and ultimately reduce the system transition time and improve the quality of power supply voltage. Finally,a dual-mode power supply system is built based onelectromagnetic transient simulation software PSCAD / EMTDC. Simulation results verify that the proposed strategy caneffectively suppress the transient rush caused by the switching between modes of voltage control structure and realizeseamless switch.