A Multilevel Ultrahigh Gate Voltage Adaptive Closed-Loop Modulation Strategy for DC Breaker Applications

The dc breaker needs to turn-off the surge current several times the insulated gate bipolar transistor (IGBT)-rated current value, the gate voltage modulation strategy is crucial. At present, the IGBT driver used in the dc breaker adopts the on-state voltage drop detection, which turn-off the IGBT after the device’s current exceeds a specific value. However, this strategy is unsuitable for various fault current that need to be removed in practical dc breaker applications. This article proposes an adaptive closed-loop modulation strategy realized by multilevel pull-up IGBT gate voltage to ultrahigh level (exceeds manufacturer's datasheet recommended value by more than 10 V) after IGBT overcurrent detected by a novel detection method, thereby greatly increasing the IGBT current capacity. Parameters, performance enhancement, and impact on device reliability are obtained through analysis. By building an equivalent diode bridge prototype that simulates the actual dc breaker applications, the effectiveness of the strategy proposed in this article is verified. The strategy proposed in this article can reduce the cost of dc breaker transfer branches by more than 80%, greatly increase the device lifetime with the same switching capacity, significantly reduce equipment costs and volume, and provide new ideas for dc breaker device selection.