Active Stabilization of Self-Excited Switched Reluctance Generator Supplying Constant Power Load in DC Microgrids

The voltage control problem of self-exited switched reluctance generator (SRG) supplying a constant power load (CPL) is investigated here. Due to the uncertainties in SRG dynamic and load, conventional linear controllers may not solve the problem and voltage oscillation inevitably appears at high load powers. This article describes a series-damped passivity-based control (PBC) scheme, considering the dynamic performance of SRG, in the presence of CPL. The main objective is to achieve a large-signal stabilization of the output voltage of generator taking into account the uncertainties of SRG. The time-varying nature of back electromotive force (EMF) of SRG is considered by calculating the bound of damping injection terms. By an adaptation mechanism to deal with the time-varying inductance and back EMF, together with the proposed PBC, a large-signal active damping adaptive-passivity-based controller (APBC) is obtained to reduce the output voltage oscillations. The effectiveness of the proposed control scheme in stabilization in SRG and CPL and voltage ripple reduction is demonstrated, using a four-phase, 8/6 pole drive system.