Evaluation of carrier-based control strategies for balancing the thermal stress of a hybrid SiC ANPC converter

SiC devices have recently been demonstrated and utilized in many different multilevel topologies. Active neutral point clamped (ANPC) converter is one of those topologies, where the use of SiC devices can significantly increase the converter power density and reduce the output filter size. In order to achieve this, the control algorithm needs to be tailored to utilize the advantages of each power device technology. Therefore, the control strategies which could produce the optimum results for Si based ANPC might not be the optimum choice for hybrid configuration, where Si and SiC devices are mixed. In this paper, it is presented how different pulse-width-modulation (PWM) based algorithms, originally proposed for Si ANPC converters, affect the loss and junction temperature distribution of a hybrid ANPC converter. The analysis includes the inverter and rectifier operation mode, as well as a high and low modulation index operation. The device junction temperatures distribution is verified using an open module 3-level hybrid ANPC prototype.