基于无功电流注入的光伏逆变器低电压穿越策略

Low voltage ride-through strategy of PV inverter based on reactive current injection

大量的光伏电站接入电网,为了提高电力系统的稳定性,需考虑光伏发电的低电压穿越能力。文章基于无功电流电压支撑方案,提出使用电流单环控制的低电压穿越策略,当电网电压因故障而降低时,逆变器由电压电流双环控制切换到电流单环控制,升压电路由最大功率控制(MPPT)切换到稳压控制。经仿真表明,所提出的电流单环控制策略能在电网发生故障时,有效的完成电压的稳定过渡,实现低电压穿越,具有实用价值。

A large number of photovoltaic power plants have been installed and connected to the grid,which requires low voltage ride-through（LVRT） of PV to improve the stability of the power system.Based on reactive current support scheme, a LVRT method of single-loop control strategy is proposed in this paper, when the grid voltage dips by a fault, the inverter operation is switched from the voltage and current duel-loop control strategy to the current single-loop control, the booster circuit is switched from the power maximum control（MPPT）, to the regulator voltage control. The simulation results show that the single-loop current control strategy can effectively keep voltage stability, achieve LVRT, which is seemed to be applied.