Development of a 40kV Series-connected IGBT Switch

A 40 kV IGBT switch has been developed, which consists of 36 series IGBT devices used for main switching and 6 series IGBT devices used for transient-voltage regulation. The IGBT switch do not only switch DC 40 kV-180 A, but also can shut off short-circuit current fast and turn on again quickly (10ms later after the short-circuit). Also, a protection circuit has been developed against IGBT open mode fault which results in critical situation such as arcing. The protection circuit detects over-voltage caused by the open mode fault and restricts the more rise of the voltage. This protection circuit enhances the reliability of the IGBT switch very much.