电压源型变换器中电流控制系统的等效电路模型

Equivalent Circuit Model of Current Control System in Voltage Source Converter

本文提出一种电流闭环控制系统的等效电路模型,便于分析与优化系统设计。在该模型中,控制器看作是电阻、电容和电流源等的组合,并给出控制系统直观的物理模型。基于该模型,可以直观地得到电流控制型VSC的谐波模型,而且控制器参数能以标幺值表示,便于不同的系统之间进行比较。根据电路理论,实现无误差波形跟踪有且只有两种方式,提出一种复合前馈控制策略来抑制稳态和动态电流跟踪误差。该控制策略在电流指令包含各种频率成分时尤为有效。仿真与实验结果证明了本文提出的电路模型的精确性以及所提出的控制策略的有效性。

In this paper,an equivalent circuit model of closed-loop current control system is presented,which is convenient for analysis and optimization of system design.In this model,the controller is considered as a combination of resistance,capacitance,current source etc.and an intuitive physical model of the control system is given.Based on this model,the harmonic model of current-controlled VSC can be obtained intuitively,and the controller parameters can be expressed as per unit value,which is convenient for comparison between different systems.According to the circuit theory,there are only two ways to realize the error free waveform tracking,a compound feed forward control strategy is proposed to suppress the steady and dynamic current tracking errors.It is noted that this control strategy is especially effective when the current instruction contains various frequency components.Finally,the Matlab/Simulin simulation and experimental results demonstrate the accuracy of the proposed circuit model and the effectiveness of the proposed control strategy.