用于三相并网逆变器稳定性分析的自导纳和伴随导纳建模

Self and Accompanying Admittance Model for Three-phase Grid-tied Inverter Stability Analysis

并网逆变器的稳定性分析通常采用导纳或阻抗的分析方法。不同于现有的序阻抗和序耦合的描述方法,采用复变量的表示方法将正负序变量统一,分析基于锁相环的三相并网逆变器的单频率输入双频率输出现象的产生机理,建立统一的并网逆变器的自导纳和伴随导纳模型,并对所建立的模型进行仿真和实验验证。依据Nyquist判据,分析自导纳和伴随导纳对并网逆变器稳定性的影响。实验结果表明,所建立的自导纳和伴随导纳模型可以获得更加准确的并网逆变器稳定性分析结果。

The admittance （or impedance）-based approach is commonly used in stability analysis of the grid-inverter system. The paper illustrated the single-frequency input double-frequency output （SIDO） phenomenon and mechanism in a three-phase grid-tied inverter based on phase locked loop （PLL） control, which was distinct from the sequence coupling in impedance model reported recently. Then the complex variable representation was used to build admittance models, making the positive and negative sequence admittances lumped into one unity admittance. Moreover, Nyquist criterion analyzed the self-admittance and accompanying admittance effects on system stability. Simulation and experimental results verified the stability analysis results are more accurate by using the proposed admittance models in stationary frame.