The overview of damping methods for three-phase grid-tied inverter with LLCL-filter

Proportional Resonant Current Control and Output-Filter Design Optimization for Grid-Tied Inverters Using Grey Wolf Optimizer

“…However, they require a detailed model of the system and its implementation is more complex [11]. In addition, when model plant mismatches are presented, this will influence the control accuracy and a significant extra sensors; and are more sensitive to parameter uncertainties [28]. As a result, designing output filters and the corresponding damping method is a complex task because efficiency and damping effect are antagonistic and interrelated goals.…”

Assessment of Grid-Side Filters for Three-Phase Current-Source Inverter PV Systems

“…The standard gridside filter topology for a CSI is a second-order CL filter with passive damping resistors [6], [7]-higher-order gridside filters may also be used despite the little attention they have received in the literature [6]. The damping resistors are commonly connected in parallel with the filter inductors-other configurations with higher losses have been proposed in the literature [6], [8].…”

“…Full-state feedback requires several extra sensors in the system. Hence, dual-loop feedback with a virtual resistor is commonly the preferred method [8], [11]- [17]. This method consists in using the feedback of one of the filter variables and subtracting it to the converter reference to obtain an effect equivalent to that of a passive damping resistor.…”

“…This method consists in using the feedback of one of the filter variables and subtracting it to the converter reference to obtain an effect equivalent to that of a passive damping resistor. The feedback variable is most often the capacitor current [12]- [15] but other variables such as the capacitor voltage or grid-side current [14] and the grid-side or converter-side inductor voltage [8] can be used. In this work, the method is applied on the filter inductor voltages and a feedback of the grid currents is used so that no extra sensor is required.…”

“…This gap has been filled with filter-based damping [10], with virtual resistor capacitor current feedback [12], [13], [15], and with the lead-lag network method [18]. Also, a single-phase circuit [13], [14] or the approximation of an equivalent single-phase system [8], [11], [12] is used in most papers to tune the active damping feedback gain. This is then applied directly to the PWM reference generation [11]- [14] or separately for i d and i q [10], neglecting the cross terms in the analysis.…”