具备带不平衡负载功能的虚拟同步机控制策略

Virtual Synchronous Generator Control Strategy with Unbalanced Load

当虚拟同步机(VSG)孤岛运行时,不平衡负载的接入会导致其输出电压不平衡。首先分析了不平衡负载条件下VSG输出电压不平衡的机理,提出了基于PR和PI复合控制的VSG电压环路控制方法;其次,考虑到VSG输出电流的d,q轴分量在负载不平衡时含有二倍频波动分量,导致VSG定子电气方程输出电压的d,q轴指令呈现二倍频波动,提出采用电压环PI调节器输出电流指令作为定子电气方程的电流输入;再次,针对不平衡负载条件下有功功率和无功功率含有二倍频分量问题,提出一种采用电压环PI调节器输出电流指令的功率直流分量提取方法;最后,仿真和实验结果证明了所提方案的有效性。

When the virtual synchronous generator(VSG)is running in island mode,unbalanced load will lead to unbalanced output voltage of VSG.To solve this problem,the principle of VSG output voltage with unbalanced load was analyzed firstly,and the VSG voltage loop controller based on proportion resonant(PR)and proportional integral(PI)was proposed.Secondly,since that the VSG output current of d,q axis component contains second harmonic when the load is unbalanced,and the output d,q axis voltage command of VSG stator electrical equation contains the second harmonic component,the voltage loop PI regulator output current command was proposed to be used as the current input of the stator electrical equation.Thirdly,since the problem that the active power and reactive power contain double frequency component under the unbalanced load,a power calculation method using the output current command of voltage loop PI regulator was proposed.Finally,simulation and experimental results show the effectiveness of the proposed scheme.