A Simplified DC-Bias Injection Method for Characterizing Power Magnetics Using a Voltage Mirror Transformer

This letter presents a simplified dc-bias injection circuit utilizing a voltage mirror transformer configured in a unique way for improved equipment applicability and measurement accuracy. A mirror transformer can minimize the impact of the reflected actuation voltages on the dc source and improve the quality of the dc-bias injection. By combining the dc-bias and ac-actuation current, the traditional three-winding dc-bias measurement setup was simplified with improved accuracy and reduced equipment complexity. The dc-bias injection circuit was implemented as a part of a highly automated data acquisition system designed for fast and accurate characterization of power magnetic materials under a wide range of operating conditions.