Determination of Centralized/Decentralized Snubbers Power Capacity for Series Connected Devices in Inductive Loads

The series connection of the power devices including insulated gate bipolar transistors (IGBTs) and metal oxide semiconductor field effect transistors (MOSFETs) has numerous applications, especially in high voltage/power converters. However, the series connected devices provide considerable privileges over high-voltage single devices, but their series stacking faces serious challenges. This paper aims to scrutinize the problems regarding the equal voltage balancing of the series of connected devices. The power loss capacity determination of the passive snubbers is a crucial task in the series connection of the devices due to the probabilistic behavior of the delays in the operation of devices. This issue is more dominant in inductive load switchings that exist in high-voltage DC-DC converters and inverters. This paper provides expressions for the power loss capacity determination of centralized and decentralized snubbers. The dependency of this power loss from the switching frequency, the number of devices, and the delay time interval are revealed. The detailed PSPICE simulations prove the validity of the obtained expressions.