Reverse Voltage Blocking Switches Using Paralleled GaN Devices for Current Source Inverter Applications

Reverse voltage blocking devices (RVB) find their applications in many converters including current source inverters (CSI). Being commercially unavailable, two devices can be connected in anti-series to make a RVB. To increase the current carrying capability, two/multiple devices can be paralleled which makes the dynamic current sharing difficult because of layout mismatches. This becomes more critical when involving GaN based devices as they are layout sensitive devices. This paper designs a 120 A RVB device by using four GaN devices. It has been shown that the paralleled devices experience almost similar gate and drain voltages when operated until 400 V, enabling equal dynamic current sharing. The resulting device was configured in a CSI where an existing double pulse test (DPT) was modified to identify the role of passive phase onto the performance of the switching devices. The paper quantified the error in switching energies to be around 7 % while including the passive phase. In the end, the developed RVB switches were used to develop a three phase current source inverter which was operated continuously to show output during RVB as well as bidirectional operating modes.