Implementation possibilities of hybrid IGBT-IGCT switches in three-level NPC inverters

Purpose - This paper aims to present an analysis of a hybrid high-voltage switch based on the parallel connection of IGBT and IGCT. The proposed configuration combines the advantages of both semiconductors, resulting in substantially reduced power losses. Such energy efficient switches could be used in high-power systems where the requirements of high switching frequency or decreased cooling systems are a major concern. Design/methodology/approach - The operation Principle of the switch is described and simulated. The power dissipation is estimated at different operation conditions. Further, the implementation possibilities of the proposed switch configuration in a three-level NPC inverter are analysed. The operation with the proposed PWM control algorithm is simulated and inverter power loss distribution is estimated. Findings - According to estimations, the proposed hybrid switch configuration allows the reduction of total losses in semiconductors by at least 50 percent. If two of these switches are used in a three-level NPC inverter as outer switches, the total losses of the inverter are reduced by 27 percent, at the same time the losses in the most stressed semiconductor device are reduced by a factor of 2.25. Therefore, achieving higher power density is possible. Practical implications - The proposed switch configuration is intended for high-power (>500 KVA) industrial, marine and railway traction systems, such as FACTS and high power variable frequency AC drives. Originality/value - The paper presents the novel energy-efficient high-voltage switch based on the parallel connection of commercially available IGBTs and IGCTs.