Voltage feedforward control of lcl grid-connected inverter based on virtual inductor

In this paper, a non-ideal generalized integrator is proposed from the perspective of control theory to approximately equivalent replace the differential terms in the positive feedback loop; Virtual equivalent inductance is introduced, Then the phase Angle compensation function is connected in series in the voltage feedforward channel to solve the phase offset problem, finally voltage feedforward control system based on virtual inductance was proposed to improve the system's ability to adapt to weak power grid. This paper analyzes the unstable mechanism of time-varying weak power grid system caused by voltage feedforward, the principle and design of approximate equivalence, and the method and logic of implementation. Finally, the correctness of the theoretical analysis and the robustness of the control strategy are verified by constructing a system simulation. © 2020, Solar Energy Periodical Office Co., Ltd. All right reserved.