Practical Design Aspects of SHE PWM Controlled 1ph. STATCOM

Abstract

This paper addresses the key issues of design and implementation of Selective Harmonic Elimination (SHE) PWM controlled 1ph. STATCOM. A simulation model of 25kV, +/- 600kVAR STATCOM is presented. The total capacity of 600kVAr is divided into eight parallel connected modules of +/-75kVAr, connected at the secondary of a 25kV/425V transformer. On-line control technique of SHE PWM Voltage Source Inverter (VSI) is proposed. The technique is based on on-line solution of 7th order polynomial equations approximately representing SHE solution trajectories, relating SHE switching angles and modulation index, m. A methodology for selection of passive components is also proposed. A robust phase synchronization technique based d-q transformation is used to maintain rigid phase locking. A prototype of the 230V, +/- 20kVAR, 1ph. STATCOM module is built to test the effectiveness of the on-line VSI control technique. The 20kVAr STATCOM is controlled by a 16 bit-fixed point processor (TMS320LF2406). Simulation and experimental results of are in good agreement and show the prowess of the developed prototype.