Aliasing Suppression of Multisampled Current-Controlled LCL-Filtered Inverters

Multisampling control provides an attractive way to reduce the delays in LCL-filtered grid-connected inverters. Thereby, bandwidth and stability margin will be improved. However, high-frequency switching harmonics (SHs) are introduced loop when inverter-side current is sampled. To investigate effect of multisampled SHs, relationship between double-update pulsewidth modulation (PWM) multiupdate PWM deduced through geometric deduction. It shown that equivalent with sampling instant shift, Nyquist frequency equal frequency. Moreover, nonaveraged value sampled within one period aliased low-order appear grid-side current. Hence, filtering SHs necessary, improved repetitive filter (IRF) proposed remove all keep advantage phase boost using multisampling control. The method evaluated a single-loop control, its effectiveness verified simulation experiment.