电网支持型变流器输出建模、控制及稳定性分析

电网支持型变流器逐渐取代传统同步机电源是构建新型电力系统的必然趋势.电网支持型变流器采用双环控制的目的和物理意义尚未形成统一结论.首先,为解释双环控制中电流内环的本质,由电流内环的离散根轨迹曲线分析电流内环的阻尼特性,从虚拟阻抗的角度分析其物理意义.其次,为快速准确获得双环控制器参数,避免反复迭代,考虑数字控制系统采样...

Analysis of modeling, control and stability for grid-supporting power converters

Grid-supporting power converters are gradually replacing the traditional synchronous machine power supply.It is an inevitable trend as new power systems are built.There is not a consensus on the purpose and physical meaning of dual-loop control for grid-supporting power converters.First,in order to elaborate the essence of inner current loop in dual-loop control,this paper analyzes damping characteristics of the current inner loop from the discrete root locus curve and addresses physical meaning from the perspective of virtual impedance.Secondly,to obtain the parameters of dual-loop controller quickly and accurately,avoiding iterations,and considering the delay caused by the sampling,calculation and PWM modulation of the digital control system,the inner loop uses a proportional controller to adjust the damping characteristics of the current inner loop.The proportional coefficient of the current controller is obtained from the optimal damping.The coefficients of the voltage controller are determined by the requirements of the closed-loop output gain at the filter resonance frequency and compensating offset angles of harmonics.Finally,simulations and experimental results have verified the effectiveness of theoretical analysis.