A simple and accurate efficiency measurement method for power converters

The accurate measurement of efficiency in wide band-gap semiconductor based converters, wherein efficiencies over 98% are achievable, is a challenge. In this work, a simple, open-loop, experimental dc-ac-dc back-to-back power conversion methodology is presented for the measurement of the combined losses of the power converter and passive filter. Additionally, only the power loss needs to be supplied by the source, although each converter sees active loading. The open-loop control mechanism for real and reactive power (power factor) control is explained, and also accuracy comparison with typical input and output power measurement method is provided. The simulation results of the proposed method are presented with experimental validation using a 1200 V SiC MOSFET based 4.6 kW - single phase (equivalent to 13.8 kW-3 phase) back-to-back conversion system.