CVCF Inverter Based on Nonlinear Control of Instantaneous Active and Reactive Power and its Operation Characteristics

Abstract

This paper describes a direct-power-controlled CVCF inverter and presents its experimentally examined operation characteristics. The most important feature of this strategy is the direct selection of the switching states of the CVCF inverter to restrict errors between the feedback and command values of active and reactive power. In addition, this paper presents a theoretical analysis of the relationship between the instantaneous power and the switching state, which is essential for deriving a switching-state table for the controller. The feasibility of the proposed method was verified through several computer simulations and experimental tests using a 2.0-kVA prototype setup. The output voltages were confirmed to be stable sinusoidal waveforms with a total harmonic distortion of 1.13% conditions. Furthermore, excellent voltage balance was achieved by the proposed strategy even under unbalanced load conditions.