Conventional phase-locked loop (PLL) is characterized by low detection accuracy and response speed under frequency offset of grid voltage conditions. A novel digital PLL based on Doubled Second Order Generalized Integrator-Quadrature Signal Generator (SOGI-QSG) is proposed with its working principles analyzed, the model of three-phase three level voltage SVPWM rectifier built, and the framework of control strategy given. Besides, simulation results show that the new PLL has better precision and adaption under frequency mutation, and it can realize a...