Real time digital feedback control of three phase PWM inverter with quick transient response suitable for uninterruptible power supply

A digital control technique is proposed to obtain sinusoidal three-phase PWM (pulsewidth-modulated) inverter output. Sensing two line-to-line voltages the required pulse patterns for deadbeat response are computed in real time, based on the predicted voltages by an observer at 18 kHz sampling frequency. This closed-loop voltage control inherently results in a very low total harmonic distortion and a very quick transient response with less filter capacity. The authors describe the modeling technique, theoretical analysis, simulations, and experimental results.<
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