Improved Operation of SiC–BJT-Based Series Resonant Inverter With Optimized Base Drive

New semiconductor technology is enabling the design of more reliable and high performance power converters. In particular, silicon carbide (SiC) technology provides faster switching times, higher operating temperature, and higher blocking voltage. Among the new SiC devices, bipolar junction transistors (BJTs) present interesting features in terms of conduction and switching losses. However, one of the main drawbacks is that these devices have low gain, requiring high base current to activate them. As a consequence, the base drive circuit becomes more complex and the final efficiency is decreased. This letter presents an optimized base drive circuit for a zero-voltage switching series resonant inverter. The proposed circuit maximizes the driver efficiency and minimizes the driver current requirements. Moreover, the proposed circuit optimizes the power converter switching conditions, increasing the converter efficiency. The proposed base drive circuit has been tested with a SiC-BJT-based series resonant inverter applied to induction heating.