Power Quality-improved Front-end Converter Employing Space Phasor-based Current Control Technique

Abstract

This paper presents analysis of two-level front-end converter employing current error space phasor-based hysteresis controller. In general, for such current controllers with inner and outer bands, the current error space phasor moves out of inner boundary six times in fundamental cycle for sector change detection. This deteriorates shape of line current waveform. In the proposed work, sector change detection logic is developed and implemented, which uses information of instantaneous values of three line voltages. It does not demand outer hysteresis band and lookup table to detect sector changeovers. This results in improvement in waveshape of line current. Proposed controller is also tested with different dynamic conditions like load variation, overmodulation, reverse power flow and line side variations, and the results of unity power factor and low total harmonic distortion in supply side current are presented. Conventional hysteresis controller is implemented using TMS320LF2407A DSP processor, and the results are discussed for unity power factor.