Enhancing Operating Range of Discrete Trench Field Stop IGBTs for Welding Applications

摘要

Reduction of power loss is a significant feature required in welding inverter. Apart from reliability and energy saving potential, it enhances the duty cycle of the welding equipment. Alternately, cooling arrangement and heat sink requirement is less, and the machine becomes compact and lighter. Discrete Trench Field Stop IGBTs [TFSIGBT] have good conduction characteristics, but they are suitable in 1-10KHz switching frequency range. Mosfet aided switching enhances the switching behavior of TFSIGBT as the bulk of the power transfer is through the IGBT while in conduction and the Mosfet is proactive during switching transitions. This article throws some light on the application potential of discrete TFSIGBT on high frequency inverters for welding applications. The paper discusses, for a practical project, of using two apparently unmatched devices in parallel (one majority carrier and other minority carrier) for a portable 220A (input: 415V, 50Hz, 3-Φ) @60%duty cycle welding machine. This machine is suitable for up to 4mm electrode at 100% duty cycle.