The Modified Formula for PETT Oscillation Frequency in IGBT Devices

Plasma extraction transit time (PETT) oscillation will cause electromagnetic interference, which is harmful to the device operation. Thus, it is important to estimate the PETT oscillation frequency accurately to suppress this oscillation. While the existing formula for PETT oscillation frequency is approximate due to its divergent problem, in this letter, a modified formula for PETT oscillation frequency is proposed for insulated gate bipolar thyristor devices. The modified formula considers the acceleration process, which is complex but does not change with the electric field. Therefore, the divergence of the formula can be well solved by introducing the modified term. Moreover, the modified formula can be obtained straightforwardly and well match the measured oscillation frequency, which verifies the accuracy of the proposed formula.