Passivity-Based Controller Design of Grid-Connected VSCs for Prevention of Electrical Resonance Instability

Harmonic resonances in Wind Power Plants: Modeling, analysis and active mitigation methods

“…A power converter connected to the grid with electrical resonance tends to instability if there is a positive feedback of the current controller at such frequency [22], [24]. Furthermore, relative stability criteria (i.e., stability margins) are also of high importance, since systems with low stability margins are usually associated to critical overcurrents/overvoltages [22], [30].…”

“…Furthermore, relative stability criteria (i.e., stability margins) are also of high importance, since systems with low stability margins are usually associated to critical overcurrents/overvoltages [22], [30]. From the control design perspective, this objective can be formulated as a maximization of the stability margins in the range of frequencies of the current control, i.e., up to f s /2.…”

“…This technique has been shown to be specially suitable when the range of frequencies to damp is low [22], [31].…”

“…2) is unknown [22], [32]. This method aims to shape the converter admittance given Z (−1) eq n (s), so it is passive in the control range of frequencies limited by f s /2.…”

“…However, as also previously discussed, the switching devices constrain the control/sampling frequency and hence, the achievable current controller bandwidth. Then, a more accurate modeling considering time-delays seems more suitable [22], [40]. In practice, active damping techniques will be limited in a relatively low frequency range of operation technique.…”