Zhejiang University

Miao Yu

Lingxia Lu

Donglian Qi

Wei Wei

Jianing Liu

Provided is a method for analyzing the stability of a PMSG-WT connected to a weak power grid considering the influence of power control. New energy power generation mostly uses a perturbation and observation (P&O) method for maximum power point tracking, and nonlinear discontinuous links therein make stability analysis difficult. The present application analyzes the stability of the PMSG-WT connected to the weak grid system based on a describing function method, and fully considers the nonlinear discontinuous links in the power loop, thus making the analysis result more accurate. At the same time, the describing function method is a method that can quantitatively calculate the frequency and amplitude of oscillation. The analysis method of the present application can provide a powerful and good reference for oscillation suppression and controller design.

Method for analyzing stability of permanent magnet synchronous generator-based wind turbines connected to weak power grid considering influence of power control

The present disclosure disclose a vector flux weakening control system for a permanent magnet synchronous motor of an electric drive system, which includes a current closed-loop regulation module, a modulation index deviation calculation module, a current characteristic point setting module, a current compensation vector angle calculation module, a current compensation vector amplitude calculation module, a current compensation vector calculation module and a current instruction correction module. In the present disclosure, the three-phase short-circuit current of the motor is taken as the end point of flux weakening regulation, and when voltage saturation occurs, the motor control system can exit saturation; since an inverter supplies power through a power battery bus at the terminal of the motor, the terminal voltage thereof will not be as low as zero, and there is a large margin to deal with abnormal factors; by introducing a dq current and correcting it at the same time, the pressure of resisting voltage saturation can be distributed to the dq current, thus avoiding excessive deviation of an output torque caused by excessive uniaxial current regulation. According to the present disclosure, the influence of the flux weakening control process on the output torque of the drive system is reduced as much as possible while ensuring the safety of the drive system.

Growing community of inventors

Hangzhou, China

Miao Yu