Application of indirect matrix converters to variable speed doubly fed induction generators

In this work, the control of a Doubly fed induction machine using an indirect matrix converter, connected between the stator and the rotor, is presented. Unlike the traditional scheme, where two back-to-back PWM inverters are used, this converter eliminates the use of bulky DC link capacitors and provides an all silicon solution for direct AC-AC conversion, with sinusoidal input currents and close to unity power factor operation. The machine rotor currents are controlled applying vector control approach with a reference frame aligned with the stator flux vector. The scheme is experimentally verified using a 3 kW variable speed energy system prototype. A TMS320C6713 DSP is used as a control platform and experimental results are presented for operation from below and above synchronous speed both in steady state and transient conditions.