Adaptive Acquisition of Power IGBT Transients With Discrimination Circuit

The frequency spectrum of the power insulated gate bipolar transistor (IGBT) circuit originates mostly from high gradient switching and low rate conduction components. High gradient transients are captured with direct probes. Switching losses are represented with 3-D surfaces acquired with Delaunay triangulation processing. Interpolation functions are introduced, allowing the prediction of the switching loss in the entire 3-D space. 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 accuracy by two orders of magnitude. The experimental results are presented for a half-bridge converter. Measurement uncertainties are acquired with dc and impulse calibration apparatuses.