并网逆变器的电压支撑控制策略的实现

为了实现电网电压发生跌落时,并网逆变器能够支撑并网点电压的目的,通过改变并网逆变器注入到电网的参考正负序电流来控制注入到电网中的无功功率大小,采用双二阶广义积分器的锁频环(DSOGI-FLL)、准比例谐振(QPR)电流环控制方法,利用电网同步、正负序提取和电流跟踪技术实现对并网点电压支撑,达到准确的锁频和电流无静差快速响应。并通过伯德图分析,得出参数的设置规律。最终通过整个控制系统的仿真实验验证了上述控制策略的有效性。

Realization of voltage support control strategy of grid-connected inverter

In order to realize the object that the grid-connected inverter is utilized to support grid voltage in power system when the grid voltage falls, the reactive power injected into the gird is controlled according to different positive and negative reference currents injected into the grid by the grid connected inverter. The frequency lock loop of double second-order generalized integrator (DSOGI-FLL) and quasi proportional resonant (QPR) current loop control methods are adopted, and power grid synchronization, negative sequence voltage extraction and current tracking technologies are used to realize the support of the grid power voltage with accurate frequency-locking and current floating quick response. Bode diagram is analyzed to achieve the setting rule of parameters. Finally, the simulation of the whole system verifies the effectiveness of the above-mentioned control strategy.