Load Test Method Using Two Small-Capacity Power Supplies for High-Frequency Transformers in Single-Phase Dual Active Bridge Converters

This paper proposes a load test method using two small-capacity power supplies for high-frequency transformers in single-phase dual active bridge (DAB) converters operated at 40 kHz. It is experimentally verified that the total apparent power for two power supplies is only 56 VA while the rated output power of a test transformer is 1 kW. Moreover, experimental results show the accuracy of power loss measurement is improved compared to a conventional method which obtains the power loss by subtracting an output power from an input power of the transformer because in the proposed load test method the excitation loss and the load loss can be measured directly, and the range of voltage and current of the power analyzer for each power supply can be properly adjusted to the voltage and current of each power supply. This is another advantage of the proposed load test method in addition to reducing the capacity of the power supply for the load test of transformers.