Design and Evaluation of Flexible Inductors for Wearable Power Electronics

Wearable electronics and soft robotics require adaptable circuit components that maintain electrical performance under mechanical stress. For these applications, rigidity components would impair functionality, so it is essential to explore physically flexible power converters, especially the inductor. This paper presents the design, fabrication, and performance evaluation of flexible inductors using commercially available ferrite sheets as magnetic cores and Litz wire for windings. Four grades of ferrite cores were used, each tested under bending and folding conditions to simulate realistic scenarios. Electrical characteristics, including inductance retention and DC resistance (DCR), were evaluated at frequencies ranging from 10 MHz, demonstrating stability in the target operating range of 200–300 kHz. The prototypes showed consistent performance despite mechanical stress, showing a worst-case inductance decrease of 88% from the original value when folded twice. The impedance sweeps further confirmed minimal variance in the DCR among the different core grades, indicating strong mechanical resilience. This study highlights the feasibility of flexible inductors for low-power wearable applications, emphasizing their potential for integration into physically pliable applications.