Power electronics engineers grappling with the challenge of balancing size and efficiency in switch-mode power supplies, uninterruptible power systems, and electric vehicle charging stations may find their solution in nanocrystalline cores. These advanced magnetic components, offered by Magnetics Inc., are redefining design possibilities for high-frequency applications through their exceptional magnetic properties.

Magnetics' nanocrystalline cores are specifically engineered for current transformers, common-mode chokes (CMC), and magnetic amplifiers (MagAmp). These cores demonstrate superior characteristics including high permeability, low power loss, and high saturation flux density, enabling smaller component sizes with greater current-handling capacity. With a saturation flux density of 1.25T and an extensive operating temperature range, nanocrystalline-core common-mode chokes maintain stable performance even under high-temperature conditions and current imbalances.

Compared to traditional ferrite cores, nanocrystalline cores offer significant improvements:

• Wider temperature range and higher high-frequency impedance: The material maintains stable magnetic properties across broader temperature variations while demonstrating increased impedance at high frequencies—critical for noise suppression.
• Enhanced resistivity: The high resistivity reduces eddy current losses, improving overall component efficiency.
• Exceptional frequency response and efficiency: Consistent performance across wide frequency ranges ensures optimal operational efficiency.

These advantages make nanocrystalline cores particularly suitable for:

• Switch-mode power supplies (SMPS) for improved efficiency and reduced size
• Uninterruptible power supplies (UPS) ensuring stable operation during power outages
• Solar inverters enhancing energy conversion efficiency
• Variable frequency drives for precise motor control
• EMC filters for effective electromagnetic interference suppression
• Electric vehicle chargers enabling rapid, efficient charging

To accommodate different applications, Magnetics provides nanocrystalline cores in multiple configurations including toroidal, cut-core, slotted, and segmented designs. The cores can be optionally housed in durable enclosures made from polyester (rated for <+130°C) or Rynite® polyester (rated for <+155°C), making them suitable for applications using heavy-gauge windings.

The exceptional performance of nanocrystalline cores in high-frequency applications stems from their unique microstructure. Rapid solidification technology produces metal alloys with nanoscale grain structures that deliver superior soft magnetic properties. This microstructure provides three key advantages:

• High permeability: The nanocrystalline structure eliminates grain boundary obstructions to magnetic domain movement, enabling easier flux concentration and enhancement.
• Low coercivity: The cancellation of anisotropic magnetic fields within the nanocrystalline structure reduces coercivity, thereby decreasing hysteresis losses.
• High saturation flux density: The material withstands stronger magnetic fields without saturation, increasing power handling capacity.

As critical components for common-mode interference suppression in SMPS and variable frequency drives, nanocrystalline-core common-mode chokes offer distinct benefits:

• Compact size: High permeability allows achieving required inductance with fewer windings, reducing component size.
• Greater impedance: Enhanced high-frequency impedance more effectively suppresses common-mode interference.
• Improved thermal stability: Temperature-independent magnetic properties ensure consistent performance in high-temperature environments.

As power electronics technology advances, demanding higher performance from magnetic components, nanocrystalline cores are poised to play an increasingly vital role in high-frequency, high-efficiency, and compact power and filtering applications. Future development will likely focus on:

• Enhancing saturation flux density through material and process optimization
• Reducing losses through microstructural refinement
• Developing new nanocrystalline materials with improved permeability, lower losses, and better thermal stability

Nanocrystalline cores represent a significant advancement in magnetic component technology, offering power electronics engineers high-performance solutions for increasingly demanding applications. Their superior characteristics and versatile configurations position them as transformative elements in modern power conversion and conditioning systems.