Automized magnetic hysteresis measurement system

Abstract

Modeling and design of magnetic components require primary data on material hysteresis properties. In this article a flexible and highly automized system is described, which is suited for the characterization of the low frequency soft magnetic behavior (≊5 Hz–2 kHz) of ferromagnetic samples. The apparatus consists of a PC with the control program, a modular data acquisition/signal generation system, and a remotely controllable power amplifier to which the sample is connected. Integration of the secondary output voltage is performed digitally. The system operates in current control mode, and the user can select from a variety of adjustable excitation functions and even complex measurement procedures. It is possible to perform stationary or transient measurements of major and minor loops, initial magnetization and commutation curves, to do automatic demagnetization, and to output specific parameters which are necessary for sample characterization or model calibration. Amplitude selection and autoscaling of the measurement sensitivity can proceed within wide dynamic ranges. Sample, signal parameter, output, and characteristic data can be printed or plotted, edited, saved, reloaded, or changed in format. A number of different options for measurement and postprocessing are available. Instead of B(H) also M(H) or μ (H) curves or time signals can be displayed. Future software versions will also support the voltage control mode (which is already provided in the amplifier), and the measurement of the anhysteretic curve. A selection of example measurements obtained for two samples and with different types of excitation signals indicates the suitability of the system for various applications.