Stability Influence of Filter Components Parasitic Resistance on LCL-Filtered Grid Converters

This paper presents the equivalent series resistance (ESR) modeling method of filter components and its stability impact of LCL filtered grid-connected voltage-source converters (VSCs). First, the time-domain models of filter inductor and capacitor are developed for modeling the ESR effect, which are used in simulations. Then, the current control loop gains of the grid-connected three-phase VSC, which include the ideal LCL filter and the ESR-modeled LCL filter are compared. The result shows that the ESR affects both the resonance peak and the phase characteristic in the frequency domain. Finally, in order to verify accuracy of proposed model, the loop gain is measured by network analyzer in the experimental set up, which shows that the analytical loop gain with proposed ESR modeled inductor agrees very well with experimental value. This verification means that the ESR modeling method is useful for an accurate stability analysis.