Analysis, design and digital implementation of a shunt active power filter with different schemes of reference current generation

To reduce the harmonics injected by non-linear loads, power quality improvement devices like shunt active power filters (SAPFs) are commonly employed. This study presents a digital signal processor (DSP) TMS320LF2407A based hardware implementation of current error space phasor-based hysteresis controller for SAPF. The proposed controller-based SAPF allows precise compensation of harmonic currents. Design considerations for practical implementation of the proposed space phasor-based current error hysteresis controller for SAPF are explained here. Performance analysis of space phasor-based current error hysteresis controller for SAPF is explained in the study. The controller´s self-adaptive nature is studied for different logics of necessary sector changes. Here, the versatile nature of the controller is proved by analysing its performance for different reference compensating current generation methods. The proposed controller works on the principle of switching voltage vectors adjacent to the desired output voltage vector of SAPF (voltage vector at the point of common coupling). This strategy helps in restricting the current error within the desired hexagonal boundary. A comparative study of DSP-based implementation for two different schemes of reference compensating currents generation is presented in this study. Instantaneous reactive power theory and Fryze current computation methods are chosen for this comparative study. Experimental results of reference compensating currents generated by different strategies using DSP are presented in this study.