Low-Loss High-Performance Base-Drive Unit for SiC BJTs

A 6kW, 200kHz boost converter with parallel-connected SiC bipolar transistors

“…The measured power consumption of the 4x2SRC driver was 7.53 W at a switching frequency of 200 kHz and 50% of duty ratio. This value is in agreement with previous results achieved for 2SRC -1.78 W at 100 kHz [8] as the switching frequency is higher.…”

“…In the case of the boost converter, the concept of the dual-source driver with resistors and capacitor (2SRC) is an interesting solution [8] as it offers very good dynamic performance together with low power consumption. The main idea of the driver is that these two functions are performed separately.…”

“…Transients in the LC circuit, consisting of the base capacitor and the stray inductances of the driver, results in adverse high-frequency oscillations and, hence, a damping resistor R DP is necessary. This solution of the base driver was designed and successfully employed to drive the 6 A BJT operating in the 100 kHz/2 kW dc/dc boost converter presented in [8]. The measured power consumption of the 2SRC driver at 50% of duty ratio was around 1.6 W.…”

“…A power-loss estimation has been done based on the equations presented in [8]. It is found that an amount of 2 W per transistor for a switching frequency of 200 kHz and a duty ratio of 50% is expected.…”

“…However, in some topologies, such as the dc/dc boost converter, reverse conduction is not required and hence the SiC BJT seems to be a good candidate among various power devices for such converters if high efficiency and high switching-frequency are both required. A 2 kW dc/dc boost converter where a 1200 V/ 6 A SiC BJT is employed and having an efficiency of approximately 99.0% at 100 kHz of switching frequency has been presented in [8]. This 2 kW dc/dc boost converter was also compared to a 2 kW boost converter employing a 1200 V SiC JFET.…”