A novel DC-link voltage synchronous control with enhanced inertial capability for full-scale power conversion wind turbine generators

The new power system is characterized by high penetration of renewable energy sources and a high proportion of power electronics (namely, double-high). The grid-forming control is an effective method to improve the grid-connected stability of wind turbine generators (WTGs) in the "double-high" grid. The control method based on the DC-link voltage can effectively realize the grid-forming control for WTGs. However, there is a disadvantage that the DC-link voltage cannot be maintained at the given value. To address this, the grid synchronization mechanism of DC-link voltage is explored and the specific implementation of a novel DC-link voltage synchronous control applicable to full-scale power conversion WTGs is proposed. Then, the boundary of the inertial coefficient is probed through the state-space method. And a compensation control is proposed to enlarge the inertial response capability based on the mechanism of damping characteristics. Finally, the PSCAD/EMTDC simulation and RTLAB hardware-in-loop experiment show that the synchronization frequency can accurately map the grid frequency changes in real-time under the premise that the DC-link voltage remains constant. In addition, the inertial coefficient can be increased by more than five times with the compensation strategy, which can enhance the support capability of the WTGs to the power grid. The grid-forming control is an effective method to improve the grid-connected stability of wind turbine generators (WTGs) in the "double-high" grid. To address the above problems, a novel DC-link voltage synchronous control for the full-scale power conversion WTG is proposed, where the grid-side converter can maintain the DC-link voltage at the given value while the control output synchronous frequency can accurately reflect the grid frequency changes in real-time for performing inertial response function. image