Variable structure power control under different operating conditions of PM synchronous generator wind farm connected to electrical network

The enlarged penetration of wind power into electrical network brings challenges to control strategies of variable speed wind energy conversion systems (VS-WECS). In this study, a nonlinear control scheme for wind farm system (WFS) is proposed. The control technique is realised using variable structure sliding mode control (VSSMC). The generator side rectifiers control is used to keep the generator rotor velocities at an optimal value obtained from the maximum power point tracking (MPPT) algorithm to maximise the total extracted power. The grid-side inverter injects the generated power into the AC network, regulates DC-link voltage and it is used to achieve unity power factor. The simulation results demonstrate the effectiveness of the proposed VSSMC strategy in different scenarios, and their advantages are shown in comparison with a conventional proportional integral (PI) control approach under grid fault conditions and the possible presence of uncertainties.