Discriminative acquisition of power IGBT low rate transients

The frequency spectrum of the power IGBT circuit originates mostly from high gradient switching and low rate conduction components. A chopper circuit is introduced for the acquisition of the IGBT low rate transients in the conductive stage of operation. A Zener discriminator enhances the measurement accurateness by two orders of magnitude. The experimental results are presented for a half-bridge converter. Measurement uncertainties are acquired with DC and impulse calibration apparatus.