The accuracy of grid synchronization is sensitive to the dc offset of grid voltage. In order to solve the problem

a decoupling hybrid frame phase-locked loop (PLL) based grid synchronization method is presented. First

the basic principle and disadvantages of the conventional synchronous frame PLL are discussed. And then

a new stationary and synchronous frame grid synchronization method is proposed by integrating the multiple synchronous frame PLL with the idea

whose dc component is considered as a 0 Hz ac harmonic. The parameters of the proposed PLL are designed from the angle of the system phase margin

disturbance rejection and dynamic performance. Finally

simulation and experimental tests are carried out under the unbalanced

distorted and dc offset conditions. The results have verified the feasibility and effectiveness of the proposed method.