Acceleration technique of flux waveform control with FPGA

Abstract

The magnetic flux density waveform is controlled to a sinusoidal wave for quantitative measurement in AC magnetic property measurement. The magnetic characteristics are nonlinear and it is difficult to make the magnetic flux density waveform sinusoidal. Therefore, the magnetic flux density waveform is made into a sinusoidal wave by feedback control (Kaido et al., 1998). Feedback control is performed by differential control, but in the non-linear region of high magnetic flux density, the convergence of the waveform is deteriorated and measurement time is increased.In this research, we succeeded in shortening the control time by using FPGA (Field-Programmable Gate Array) as the magnetic flux density waveform control method. The waveform control method sets various initial conditions in the PC, and is sent to the FPGA together with the target voltage waveform data. The FPGA starts feedback control from the information.The magnetic flux density was measured from 0.1 T to 2.0 T by using a single sheet tester and setting the amplitude ratio and the strain ratio to 0.5% or less using 50A1300 and 50A470. As a result, it has succeeded in significantly speeding up compared with the device which controls the waveform only with the conventional software.