High-Performance High-Power Inductor Design for High-Frequency Applications
Mansi V. Joisher, Roderick S. Bayliss, Mike K. Ranjram, Rachel S. Yang, Alexander S. Jurkov, David J. Perreault
Abstract
Magnetic components significantly impact the performance and size of power electronic circuits. This is especially true at radio frequencies (rf) of many MHz and above. In the high-frequency (HF, 3-30 MHz) range, coreless (or "air-core") inductors are conventionally used. These inductors have typical quality factors of 200-500 and are often the major contributor to a system’s overall loss and size. Even when they can achieve high-Q, air-core inductors can induce electromagnetic interference (EMI) and eddy current loss in surrounding components, thus limiting system miniaturization. With recent advances in high-frequency magnetic materials, there is interest in design of cored inductors to achieve improved combinations of size and loss. This work investigates an approach to achieving high-power, high-frequency, high-Q cored inductors. The proposed design approach leverages high-frequency magnetic materials, core geometry, quasi-distributed gaps, and a shield winding to realize high-frequency inductors that emit little flux outside their physical volume. Design guidelines for such inductors are introduced and experimentally verified with a 500 nH inductor (Q = 1150) designed to operate at 13.56 MHz with a peak ac current of up to 80 Amps.