Comprehensive evaluation of three-phase ac-ac PWM converter systems

Three-phase ac-ac PWM converters with voltage or current dc-link are employed for electric drives requiring bidirectional power flow and a high input power factor. For more than thirty years matrix converters have been considered to offer significant advantages over the conventional two-stage concepts with dc-link energy storage in terms of power conversion efficiency and volume of passive components. However, despite intensive research, matrix converters are still not widely used in industry. One possible reason for their limited utilization is the complex modulation scheme required to perform rectification and inversion simultaneously in one stage. The main objective of this Tutorial is to introduce the participant to matrix converters as well as voltage and current dc-link based converter systems in a figurative and easy-to-follow way. Starting from the voltage dc-link and current dc-link converter topology, various matrix converter topologies are derived and the related modulation and commutation schemes are introduced. Subsequently, the matrix converter concept is compared for drive applications against competing converter topologies with dc-link energy storage regarding efficiency, admissible torque-speed operating range, volume of passive components, and EMI filtering effort. Furthermore, a semiconductor chip area based assessment of the different converter concepts is given, which provides a further distinct criterion for comparison. The scope of the Tutorial not only includes bidirectional converters but also converter topologies with unidirectional power flow, which allow to reduce the number of power semiconductors and to decrease the overall realization effort and volume. The Tutorial aims at providing the participants with different figures-of-merit to select the most suitable converter concept for a given application and to assess the influence of future advancements in power semiconductor technology regarding performance gain of converter systems.