Analysis of Negative Vce which can be generated in PFC IGBT under the Low Input Voltage Condition

In medium and high power system, IGBT is used as power switch for PFC block with boot diode. In the case of power MOSFET, there are monolithic anti-parallel diode which is called as body diode. However, IGBT does not have anti-parallel diode. If anti-parallel diode is not used with IGBT, unexpected large negative Vce can be generated at low input voltage condition. Level of negative Vce depends on voltage difference between output and input voltage combine with load inductor and IGBT parasitic capacitance. In this paper, reason of negative Vce generation in PFC IGBT will be explained and recommended prevention method will be presented based on the simulation result.