正负序电流控制对电压源型变换器谐波稳定性的影响研究

Research into the Influence of Positive and Negative Sequence Current Control on the Harmonic Stability of Voltage Source Converters

为了保证电压源型变换器在非对称电网下正常工作,其电流控制中需包含正序电流控制和负序电流控制.在建立电压源型变换器阻抗模型的基础上,研究并对比基于延时的正负序分解法和基于二阶广义积分器的正负序分解法对电压源变换器谐波稳定性的影响.研究结果表明,与基于二阶广义积分器的正负序分解法相比,基于延时的正负序分解法将引入更高的不稳定性风险.时域仿真结果验证了本文理论分析的正确性.

To ensure the normal operation of voltage source converters in unbalanced power grids,positive sequence current control and negative sequence current control should be included.Firstly,a model for impedance of voltage source converters is built.Then,the influence of the delay-based positive and negative sequence decomposition method and the second-order generalized integrator-based positive and negative sequence decomposition method on the harmonic stability of the voltage source inverter is studied and compared.The results show that compared with the second-order generalized integrator-based positive and negative sequence decomposition method,the delay-based positive and negative sequence decomposition method will introduce higher instability risks.Finally,theoretical analysis is verified through time-domain simulation.