State-feedback control of a voltage source inverter-based STATCOM

Comparative analysis of several linear controllers with developed feedback controllers for DSTATCOM

“…The state feedback controller is an efficient tool to control the transient and steady-state response (Shukla et al, 2007;Mishra et al, 2003;Reed et al, 2000;Singh and Solanki, 2009;Schauder and Mehta, 1993;Wang et al, 2012;Gupta and Ghosh, 2006;Bajpai and Gupta, 2010;Arya and Singh, 2014;Elnady and Salam, 2005;Singh and Arya, 2012;Singh et al, 2014a;Ajami and Asadzadeh, 2012;Pradeepa et al, 2013;Vardhana et al, 2009;Rao et al, 2000). The LQR is a dominant technique that has been used to relocate the closed loop eigenvalues at desired locations, but its main problem is its inability to directly determine the desired location for the eigenvalues though matrices Q, R, even there is no a direct rule to select matrices Q, R for the optimum performance, but they have been commonly selected through trials and errors as presented in Rao et al (2000), Anshuman et al (2007) and Arindam and Gerard (2003).…”

“…Some other feedback controllers have been utilised with DSTATCOMs. The state feedback controller is utilised with DSTATCOMs to relocate the eigenvalues of the whole system so that the transient, steady-state performance and the injected reactive power are improved (Ajami and Asadzadeh, 2012;Pradeepa et al, 2013;Shukla et al, 2007). Actually, the utilised state feedback controller (particularly linear quadratic regulator -LQR) gives satisfactory, not excellent, results since the transient performance suffers from a considerable overshoot in V dc , but the decoupling between the state variables (I q -V dc ) is still a problematic issue.…”