Semiconductors current efforts and losses evaluation for single-phase three-level regenerative PWM rectifiers

Ac electronic loads are of interest in applications such as loss measurements in distribution transformers and small generators, UPS testing and other. In order to achieve high control bandwidth to inject current harmonics, it is important that EMC filters use small value passive components. Based on this requirement, three-level regenerative rectifiers are able to achieve better performance than two-level ones. Two candidate topologies for the implementation of a high performance 3.5 kW regenerative rectifier operating as ac electronic load are compared with respect to achievable efficiency numbers. Both topologies present the same external characteristics. The operation of the topologies is briefly reviewed in order to compute current efforts across the power devices. Based on which the losses for the converters are estimated along with their efficiency.