Passivity‐based output admittance shaping of the converter‐side current‐controlled grid‐tied inverter to improve the robustness to the grid impedance

Abstract

In the LCL-filtered grid-tied inverter, the classical low-cost control strategy which is composed of the single converterside current control and the unit grid voltage feedforward compensation, is commonly employed to inject the sinusoidal current into the utility. However, the inverter output admittance features the non-passive behaviour, which indicates that the harmonic currents may be amplified under the disturbances of the grid voltage and the grid impedance. Therefore, two dedicated current loops based on only the converter-side current feedback are proposed, which consist of the low-pass filter-based current regulation and the high-pass filter-based active damping (HFAD). The mixed asymmetrical regular sampling method is further used to reduce the control delay of the HFAD. Moreover, the low-pass filter-based feedforward is developed to make a compromise between the disturbance rejection and the stability. Fair comparisons with other typical control strategies are made through analysing the virtual resistor in parallel with the filter capacitor, which reveals that the positive virtual resistance at the frequency lower than half of the switching frequency is maintained. With the elaborated control parameters, the exhaustive experimental results finally verify the effectiveness of the proposed method in passivating the inverter output admittance.

Passivity-based stability analysis of parallel single-phase inverters with hybrid reference frame control considering PLL effect

“…According to (21), the proportional and integral coefficients (k p,PLL and k i,PLL ) of PI controller can be written as a function of PLL bandwidth ω BW [51], and ω BW = 2πf BW . Substituting the equations ( 22), (23) into equation (2), thus the T PLL can be expressed as a function with the PLL bandwidth ω BW as a variable.…”

“…Currently, the stability analysis [14][15][16][17], parameters design [13,[18][19][20][21] and control strategy improvement [22][23][24][25][26] of the gridconnected inverters have been reported based on the passivity properties of inverter output admittances. In [14], the inverter output admittance is decomposed into a passive admittance in series with an active admittance.…”

Sensor reduction of a PV‐grid tied system with tripartite control based on LCL filter

“…In addition, it also requires more sensors to sense the measuring point. Qiang et al [20] has proposed the current control strategy composed of the converter side current control and the unit grid voltage feedforward compensation to enhance the robustness of the current control of the grid-tied inverter. However, this method is not tested for the three-phase system.…”

Passivity Enhancement Strategy of Grid-Connected Inverter System Based on the Adaptive Active Damper

“…Both impedance-based and passivity-based stability criteria can be utilized to analyze the stability of the GCI system (Harnefors et al, 2016;Sun, 2011;Xiong et al, 2020;Wu et al, 2020;Liao et al, 2020). For the paralleled inverter system, the passivity-based criterion is more intuitive since it is possible to analyze the frequency band where the instability occurs, so the parameters of the whole system can be designed quantitatively (Han et al, 2022;Qian et al, 2020). Noting that the passivity is a sufficient yet unnecessary condition to ensure the system is stable, the relatively conservative analysis result can provide a large stability margin of the system (Yoon et al, 2016).…”