Verification of Iron Loss Calculation Method Using a High‐Precision Iron Loss Analyzer

Abstract

SUMMARY Because of the improved performance of power devices, the volume of the ac filter inductors used in high‐frequency PWM inverters has been reduced. However, the temperature rise in the filter inductor due to this miniaturization has become more pronounced. Therefore, we have proposed an iron loss calculation method for the ac filter inductor. However, the accuracy of the value calculated via the loss map method cannot be verified, because the iron loss arising during each switching period cannot be measured with conventional power measuring instruments. In order to resolve this problem, we developed an inductor loss analyzer (ILA), which allows precise measurement of the iron loss in the inductor during each switching period. The accuracy of the calculation of iron loss in the filter inductor by the loss map method was verified with the ILA. We found that the value calculated by the loss map method differed slightly from the value measured with the ILA. However, these differences can be reduced if we take into account the accurate flux density calculation and the effect of the duty ratio of PWM pulses on the loss. Finally, we verified that the loss map method can provide accurate iron loss calculations.

Iron Loss Calculation of AC Filter Inductor for Three‐Phase PWM Inverters

“…Iron loss obtained by ILA agree within 2% with values measured by a high-accuracy power meter (PPA5530 by Newtons4th), thus featuring high accuracy [8]. Iron loss obtained by ILA agree within 2% with values measured by a high-accuracy power meter (PPA5530 by Newtons4th), thus featuring high accuracy [8].…”

“…However, with bias components, hysteresis curve changes its position and shape depending on the bias components. 4) to describe iron loss with regard for both flux density ripple ΔB and bias field H 0 , and demonstrated its efficiency [7,8]. 1.…”

“…15, exciting voltage v L of A-phase filter inductor is a superposition of a sine wave on a rectangular wave; at the same time, sine waves are superimposed on ripple components of exciting current i L1 , flux density B, and field strength H. In addition, due to the influence from other phases, excitation waveforms are different from those of a single-phase inverter. (8), (9), and (10). (2) at the intervals a-b, b-c, and c-d in Fig.…”

“…In the diagram, excitation period t bc at the interval b-c is shorter than t cd at the interval c-d. With ILA, when switching interval is set from a to h, effective power at this interval is measured [8]; therefore, iron loss can be measured when dB/dt changes several times while flux density B increases (or decreases). With the loss map method, instantaneous iron loss is linearly approximated beyond the measurement range (equivalent frequency f = 10 kHz to 50 kHz).…”

Three‐Phase AC Filter Inductor Design for Three‐Phase PWM Inverter for Conversion Efficiency Improvement at Low Load

“…High-frequency iron loss P HF is calculated using a loss map method proposed previously by the authors [14][15][16][17][18][19]. In the loss map method, instantaneous loss Q HF (J/m 3 ) generated in each inductor waveform is calculated using a loss map, that is, a diagram plotting inductor loss characteristics with respect to dc magnetic bias field H 0 and flux density ripple ΔB at varied excitation frequency f 0 .…”