Derivation of a Single-Phase Single-Stage Inverter Based on Minimum Indirect Power

This paper presents a methodology to derive power converters when a single inductor is used. Given the current and voltage in the different ports, the modulation that minimizes the power processed in the inductor (indirect power) is obtained. The indirect power is associated with the energy stored and delivered by reactive components and the switching frequency. Therefore, it should be minimized to reduce volume and losses in the inductor. The methodology consists in the analysis of the indirect power on the possible operation modes of a converter, where operation modes are sequences of switching states. This methodology, when applied to DC-DC two-port conversion shows that the Buck or Boost converters are optimal in terms of power processed. Nevertheless, this methodology is more interesting when applied to three-port converters. In this work, it is applied to a three-port single-phase inverter where the third port is the capacitor used for power decoupling. The result is a complex topology that operates in several modes in different sectors of the line cycle with very reduced indirect power in the inductor. Finally, a simplified structure is described and implemented, providing experimental results.