Discrete-Time Adaptive PID Current Controller for Wind Boost Converter

Abstract

This paper proposes an adaptive controller for a dc-dc boost converter to regulate the output current levels of a 400 W small wind turbine based on a permanent magnet synchronous generator with a three-phase diode rectifier. Despite the stochastic nature of wind, this discrete-time adaptive PID controller regulates the current levels without large overshoots and oscillations to attain the maximum power point of the wind system. The adaptive mechanism algorithm operating with two electrical measurements adjusts the controller parameters, and is designed with an approach consisting of the integration of the variable operation point of the small wind turbine into the discrete-time model of the dc-dc boost converter and the Bode stability criteria. The mechanism algorithm features a low computational complexity for controller parameters estimation and therefor a practical implementation in a low-end microcontroller (small size, low cost, and low energy consumption) is possible. Furthermore, the results based on the processor-in-the-loop simulation approach show that controlling the current levels and the maximum power point of the wind system via the proposed adaptive controller is more effective than a controller tuned around a particular fixed operating point.