Power loss analysis and optimization of three-level T-type converter based on hybrid devices

This paper details the loss model of T-type converter using an improved method which is quite simple. The method utilizes the current and voltage information from simulation model in which the impact of the PWM methods, dead time and devices on the power losses are involved. Thus, the influences of different PWM methods and devices are analysed. Based on the results, a low-voltage three phase 10kW T-type inverter equipped with hybrid devices is implemented. Results show that the discontinuous SVPWM (DPWM1) achieves higher efficiency than continuous SVPWM. Based on the loss distribution of the devices in the bridge, the hybrid device combination of CoolMOS/FWD as main switch and IGBT/SiC diode as auxiliary switches are utilized in the prototype. It can exploit the potential of these devices. The maximum efficiency of the prototype reaches at 99.2% at 20 kHz switching frequency.