Design and implementation of a linear quadratic regulator controlled active power conditioner for effective source utilisation and voltage regulation in low-power wind energy conversion systems

Power electronic converters play a major role in wind energy conversion systems (WECS). A typical variable speed WECS includes wind turbine, permanent magnet synchronous generator (PMSG) and power conditioners. In this study, a three-phase modular boost converter supplied from a PMSG and controlled using a linear quadratic regulator (LQR) is proposed for battery charging applications. Each phase of PMSG is connected to a single phase diode rectifier and a DC-DC boost converter. All boost converters have a common output capacitor and load. The proportional-integral-based voltage controller provides voltage regulation on the DC side. A fixed frequency LQR-based current controller applied for the individual phases provides a better three-phase source utilisation. The instantaneous pq theory is adopted for the reference current calculation. Extensive simulation studies based on the models developed using MATLAB/SIMULINK reveal that the proposed system performs satisfactorily for step variations in wind speed and load. The performance of the low power prototype developed and controlled using a dSPACE 1104 digital signal processor shows good output voltage regulation and better source utilisation for wide variations in load.