Integral variable structure controllers for small wind energy systems

In this paper, two simple strategies are presented to track the optimum operating point of a wind turbine. The schemes are based on a variable structure controller with integral compensation. The integral compensation either reduces or eliminates the control signal chattering. A comparison of both control strategies is presented for the tracking of the optimum speed with a real wind profile. In addition, some practical aspects, like tuning and controller wind-up, are also considered.