Generalized Sector Detection Technique for Current Error Space Phasor Based Hysteresis Controller Applied to Multi-Level Front-End Converter

Abstract

Current error space phase based hysteresis controller requires two (inner and outer) hysteresis bands for vector selection and for sector detection, respectively. Current error space phasor moves many times out of the fixed hexagonal boundary (and touches outer hysteresis band) in one fundamental cycle to detect appropriate sector. This distorts the supply current and increases the implementation complexity. In this paper, fractal approach and triangularization techniques are proposed and analyzed to eliminate outer hysteresis band and look-up table for sector change detection. This technique is integrated with current error space phasor based hysteresis controller to make it generalized for any multi-level front-end converter. Detailed analysis of the proposed technique for sector detections is presented considering voltage space phasor structure of three-level and five-level converters. Generalized flow chart is also developed and presented for any multi-level converter employing current error space phasor based hysteresis controller with proposed sector detection technique. Experimental results for various steady state and dynamic conditions are presented to validate the technique of sector detection, considering voltage space phasor structure of threelevel flying capacitor (FC) front-end converter.