Discontinuous Modulation of a Cascaded H-Bridge Low-Capacitance StatCom

This article presents a discontinuous modulation (DM) strategy for static compensators (StatComs) based on cascaded H-bridge (CHB) converter with star configuration. The proposed DM considers the capacitor voltage oscillations at twice fundamental frequency and effect of zero-sequence injection voltages. Considering these effects is especially important in CHB-StatComs large ripples (low-capacitance StatComs), where assumption constant dc-link voltage, which basis conventional strategies, does not apply. also describes coherent set steady-state waveforms under DM. In addition to well-known benefit reducing switching losses, reduces capacitors size extends operating range. viability verified experimentally small-scale prototype. addition, simulation results are obtained using real-scale system study feasibility unbalanced conditions.