Abstract
With the realization of the wide range of voltage ratings up to 6.5-kV, IGBTs have been widely applied to various inverters as a switching device due to their features of fast switching, low switching losses and easy driving. Accordingly, a short-circuit protection for IGBTs is one of the most critical issues. This paper describes two short-circuit protection methods, we call them, “Active-controlled cut-off method" and “Passive-controlled cut-off method". The active-controlled cut-off method enables a device to cut off a short-circuit current safely by control of a gate-to-emitter voltage waveform following a memorized pattern in consideration of its short-circuit safe operating area (SCSOA) and maximum short-circuit withstand time. A short-circuit test with a 2.5-kV rated IGBT are conducted, and effectiveness of the active-controlled cut-off method is verified. For more simple protection circuit configuration suitable for inverters with lower cost and smaller size, the passive-controlled cut-off method is given. This circuit is composed only of a stray inductance in main circuit line. Experimental results with simulation and experimental results are shown here.
