State of the Art of Dv/dt and Di/dt Control of Insulated Gate Power Switches

IGBT and MOSFET power switches are commonly used in power converters. MOSFET for middle power and IGBT for high power converters : gate drive circuits are used to drive such components. Some applications need to control dv/dt and di/dt from power switches to reduce electromagnetic emissions. New solutions have been introduced and tested since 1990 (conresponding to the maturation of IGBT technology) [1,2]. We expose first consequences due to dv/dt and di/dt of power switches such as EMC problems. A theoretical approach highlights coupling phenomena between the power side and signal electronics. Conduction and emission aspects are discussed to show that dv/dt and di/dt must be reduced for some applications. Solutions to these problem cannot be proposed without understanding power switch structure and current-voltage transients. Therefore, focus is made on a theoretical approach on IGBTs (Insulated Gate Bipolar Transistor). MOSFETs (Metal Oxyde Field Effect Transistor) are considered in this part too but not described in detail. First a physical approach is proposed (structure of IGBT cell) that leads to an IGBT model. A simplified electrical model is considered that facilitates explainations on transient voltage and current. Some considerations are outlined in order to introduce proposed solutions. In proposed solutions, the authors underline solutions published in international papers and personal one. Main ideas are developped to give an overview of state of the art of dv/dt and di/dt control. Focus is made on inductance estimation of IGBT power modules necessary for di/dt control : expermiental and simulation results are compared for 1200A-3300V IGBT modules.