Comparative analysis of unit template, SRF and the modified SRF technique for DSTATCOM-based distribution system

摘要

This paper introduces a new hybrid control strategy called the modified synchronous reference frame theory (modified SRF theory) for power quality improvement of a DSTATCOM-based distribution system. This control strategy makes use of both synchronous reference frame (SRF) as well as unit template technique to generate the reference supply currents which are then compared with the sensed supply currents and fed to the hysteresis/PWM current controller to generate the necessary switching signals for switches of the voltage source converter (VSC) of the DSTATCOM for a three-phase, three-wire system. The proposed algorithm eliminates the need of a complex reverse Park's transformation and results in the most efficient harmonic diminution confirming to IEEE-519 standard. The proposed control algorithm is compared with the unit template-based algorithm and the SRF theory to mitigate a variety of problems such as low power factor, voltage regulation, current unbalance and harmonics in the system. The proposed algorithm is proved efficient and reliable when compared with conventional algorithms reported in the literature.