Because the grid voltage is usually affected by disturbance and harmonic, so in the synchronous application of grid-connected converter, there is a phase difference between grid-conneccted current and grid voltage, which will have impact and pollution to the power grid. According to the practice, some phase locked loop(PLL) based quadrature signal generator(QSG) have better performance. This paper uses the second-order general integrator(SOGI) that is improved, and frequency of SOGI automatically tracks the input frequency through a simple control loop instead of trigonometric function, finally this scheme construct new-style structure of the frequency locked loop with PLL module.This scheme is easy to design and implement, simulation results show its excellent performance, frequency and angle can be detected rapidly and do not contain a steady oscillation, the feasibility and the superiority of the scheme are verified.