Experimental Evaluation of a Back-to-Back Power Interface to Grid Integration of a Wind Turbine

This paper presents a power scheme known as back-to-back used as a power conditioner for a wind turbine system which uses a permanent magnet synchronous generator (PMSG). The back-to-back power structure consists of a three-phase pulse width modulated (PWM) active rectifier, a dc-link bus voltage and a three-phase PWM inverter. Both power conditioning structures can be operated under traditional and well known control strategies, such as the proportional and integral schemes. An experimental back-to-back power interface is designed and built for evaluation studies in the lab. Modulation techniques for the rectifier will be implemented in a dSPACE platform while for the investor was implemented in a DSP plataform to demonstrate the feasibility of the back-to-back power converter for a grid interconnection of a 5kW, 220V wind turbine system. Simulation results demonstrate that a back-to-back power converter can be operated by sinusoidal pulse width modulation (SPWM) and controlled by traditional proportional-integral schemes. Experimental results in open loop are presented for the ca-cd stage using a ds1104 dSPACE and for cd-ca stage using a Texas Instruments DSP TMS320F28335 and tested in the intelligent power module model FSBF15CH60BT to evaluation studies in the lab obtaining satisfactory wave forms and expected amplitudes. The control strategy is left for future implementation.