Gate driving of high power IGBT through a Double Galvanic Insulation Transformer

The reliability of the transmission of the switching signal of IGBT in a static converter is crucial. In fact, if the switching signals are badly transmitted, the power converter can be short-circuited with dramatic consequences. Thus, the operating of such a system can be stopped with heavy economic consequences, as it is the case for an electric train. Many techniques have been developed to achieve solutions for a safe transmission of switching signals with a good galvanic insulation. In very high-voltage, over 10 kV, an optimal solution is to use optic fibres. This technology is limited by the fibre degradation in high temperature atmosphere. Actually, this problem exists in trains. The common use of the radio frequency transmission (RFT) can be exploited to achieve an original IGBT wireless driver. This solution seems to be interesting because high temperature do not interfere with radio frequency transmission. However, radiated electromagnetic interferences (EMI) are drastically important in such an electrical environment, EMI can disturb the RFT. In order to optimise the transmission of switching signals, we have decided to transmit the signals through the energy supplying link. This last device is constituted by a double galvanic insulation transformer (DGIT). The difficulty is to transmit the energy, which is used for the IGBT driver supply and the switching signals in the same loop wire. The paper will highlight this aspect