新能源并网变流器不平衡电网电压观测方法

Unbalanced Grid Voltage Observation Method for New Energy Grid-connected Converter

常规基于二阶广义积分器的并网变流器电网电压观测方法不能实现不平衡电网电压观测,且受直流偏置影响。为此,提出了一种基于三阶广义积分器的并网变流器不平衡电网电压观测方法。此处首先介绍了基于二阶广义积分器的电网电压观测方法,并分析了直流偏置的影响。然后分析了三阶广义积分器可抑制直流偏置的优点,并提出了基于三阶广义积分器的电网电压基波分量、正交分量和电网电流微分信号观测方法。在此基础上,提出了一种基于三阶广义积分器的不平衡电网电压观测方法,消除了直流偏置的影响。实验研究验证了所提方法的有效性。

The conventional grid voltage observation method for grid-connected converter based on second-order generalized integrator cannot realize unbalanced grid voltage observation and it is affected by DC-bias.So,an unbalanced grid voltage observation method for grid-connected converter based on third-order generalized integrator is proposed.The grid voltage observation method based on second-order generalized integrator is introduced firstly,and the influences of DC-bias are analyzed.Then,the advantages of the third-order generalized integrator that can suppress DCbias are analyzed,and the observation method of the fundamental and the orthogonal components of grid voltage,as well as the differential signal of grid current,is proposed based on third-order generalized integrator.On this basis,an unbalanced grid voltage observation method based on third-order generalized integrator is proposed,which eliminates the DC-bias effects.Experimental studies verify the effectiveness of the proposed method.