It has been noticed that renewable generation such as photovoltaics and wind generation sometimes cannot stably ride through a voltage dip even if they passed mandatory grid compliance tests. This phenomenon is related to the stability behavior of the grid side converter, which connects the unit to the grid. In this work, we present a clear analysis of the stability behavior during and after low voltage ride through. This analysis includes all components and control circuits relevant for transient stability, which includes in particular the converter's phase-locked loop (PLL) and the DC link voltage control. We give analytical stability measures and present also show test results of transient characteristics of the grid-side converter. We focus on the transient characteristics of converter's PLL at the moments of fault beginning and fault clearing and the PLL's influence on the DC link voltage after fault clearing. This transient state analysis method can obtain more stable related information than the steady-state analysis method. In addition, the present test methods are analyzed from the aspect of the PLL, which turns out to be an integral part to guaranteeing stability in large-scale fault situations. Experiments based on the controller hardware-in-the-loop test verify the aforementioned analysis results. The abscissa in Figure is the output phase angle θ PLL of the PLL, and the ordinate shows the corresponding quadrature axis component of v ̲ PCC . The curves in Figure are the operation trajectories of the PLL with a defined set of parameters, including converter current, grid impedance, and nominal grid voltage. As described in the operating principle of SRF-PLL, when v PCC , q = 0 , the PLL control is in steady-state condition and the projection of the trajectory on the abscissa is the phase angle of v ̲ PCC , thus θ PLL = θ PCC . When v PCC , q > 0 , the operation point moves to a larger θ PLL value. When v PCC , q < 0 , θ PLL decreases. Within each interval 2 π of a trajectory, v PCC , q θ intersects the abscissa axis either twice, corresponding to a stable equilibrium point (SEP) or an unstable equilibrium point (USEP), or once corresponding to a critical equilibrium point (CSEP), or not at all, depending on the parameters actually describing the operation. [Display omitted] • Transient stability investigations of converter connected generation. • Definition of a simple stability measures by investigation of the relevant system parts. • Experimental verification of the results by utilizing a controller Hardware-in-the-Loop system. In a power system with a high percentage of converter coupled generation, dynamic characteristics of the converter affects the stability of the whole power system. The interaction of the various control loops of the grid-side converter, e.g., the phase-locked loop and the DC link voltage control loop, dominates the various dynamic characteristics of the grid-side converter, including its low voltage ride-through ability. In this paper, the phase-locked loop is modeled and analyzed and a stability criterion for the converter, depending on the grid impedance, is obtained. According to this criterion, a common low voltage ride-through test device based on the shunt impedance voltage sag generator is analyzed. The results show that, and explain why, the test device cannot reproduce the characteristics of the practical grid, which is also verified by experiments using a controller-Hardware-in-the-loop system. [ABSTRACT FROM AUTHOR]