Sequences Domain Impedance Modeling of Three-Phase Grid-Connected Converter Using Harmonic Transfer Matrices

Coupling-Related Instability Mechanism and Mitigation Analysis of the Instantaneous Power Based Current Controlled Inverter

“…That means the current reference of the IP-CCI just has disturbed signals at the coupling frequencies. Differently, the inner loop current reference of the traditional studied PLL-CCI contains signals mainly at the perturbed frequencies fp and fn, and only small coupling terms observed at (fp-2f1) and (fn+2f1) [16], [17], [21].…”

“…The stability analysis results indicated that ignoring the small coupling terms would lead to a wrong estimation of the system stability. Then, [17] proposed a more detailed harmonic transfer matrix to model the frequency-coupling and sequence-coupling. Additionally, sequence-couplings in single-phase grid-connected CCI have also been proposed in [18] and [19], where the coupling effect of the PLL is expressed by the multi-frequency impedance matrix.…”

High Frequency Resonance Damping Method for Voltage Source Converter Based on Voltage Feedforward Control

“…The existing damping solutions can be divided into passive damping [14,15] and active damping [16][17][18][19][20][21], while the latter is more widely used. For the grid-connected VSC, according to the different instability mechanisms, the existing damping methods can be achieved by the optimizing of PLL (Phase locked loop) [16,17] and current feedback [18,19].…”

“…The existing damping solutions can be divided into passive damping [14,15] and active damping [16][17][18][19][20][21], while the latter is more widely used. For the grid-connected VSC, according to the different instability mechanisms, the existing damping methods can be achieved by the optimizing of PLL (Phase locked loop) [16,17] and current feedback [18,19]. For the stability issue which caused by PLL, the optimizing of PLL parameters [16] and the improved PLL structure [17] are the effective methods for damping resonance, while it cannot be used for HFR damping, due to the reason that the bandwidth of PLL is much lower than the frequency range of HFR [9][10][11][12][13][14][15].…”

“…For the grid-connected VSC, according to the different instability mechanisms, the existing damping methods can be achieved by the optimizing of PLL (Phase locked loop) [16,17] and current feedback [18,19]. For the stability issue which caused by PLL, the optimizing of PLL parameters [16] and the improved PLL structure [17] are the effective methods for damping resonance, while it cannot be used for HFR damping, due to the reason that the bandwidth of PLL is much lower than the frequency range of HFR [9][10][11][12][13][14][15]. The damping methods based on current feedback [18,19] introduce a series impedance which can effectively achieve impedance reshaping at a fixed frequency point [18] or in a wide frequency range [19], thus they have been widely employed in the application of HFR damping [12][13][14][15].…”