Researchers automate core loss measurement with sub-MHz switched capacitor system

A new fully automated core loss measurement system promises to speed up and improve accuracy for designers of high-frequency power magnetic components. Developed by Haoyu Wang and Alex Hanson, the system targets sub-MHz magnetics and integrates digitally-controlled switched capacitor sequences with onboard signal processing circuits. This eliminates the need for manual tuning and computationally intensive Fast Fourier Transform (FFT) analysis that plague state-of-the-art resonant characterization methods. The switched capacitor sequence enables automatic sweeping of both frequency and drive level, providing complete characterization without human intervention. The researchers also present design guidelines for the capacitor sequence and characterize common commercial electromechanical power relays to enable sub-MHz measurements.

Experimental results across several magnetic materials demonstrate the system's accuracy and speed: it can collect more than 1,000 data points within 20 seconds. This represents a major leap over current methods that rely on labor-intensive manual tuning and slow FFT-based resonant identification. The system is particularly valuable for engineers designing power converters, inductors, and transformers operating in the hundreds of kHz to low MHz range. By automating loss characterization, the system reduces design iteration time and enables more optimal component selection, ultimately leading to more efficient power electronics.