The pulse width modulation (PWM) inverter is widely used for the control of motors. We showed that the iron loss under PWM inverter excitation is affected by the impedance of the excitation circuit. The dc voltage of PWM inverter, which is widely used, is constant and the control of motor is carried out by changing the modulation index. Therefore, the evaluation of iron loss under PWM excitation with constant dc voltage is necessary in order to investigate the behavior of iron loss in an actual motor. In this paper, we measured iron losses of non-oriented electrical steel sheets under the shingle-phase full-bridge PWM inverter excitation and examined the influence of modulation index , carrier frequency and dc voltage on the iron losses. It is shown that the iron loss under PWM inverter excitation can be reduced when dc voltage is reduced and modulation index is increased.

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SUMMARY Because of the development of power electronics technology, pulse width modulation (PWM) inverters are now being used to drive motors in order to achieve precise and energy‐efficient control. Precise estimation of the increase in iron loss due to the high harmonic components of flux, including the carrier frequency, is important in the design of motors excited by a PWM inverter. We measured the iron losses of non‐oriented electrical steel sheets that were excited using a single‐phase full‐bridge PWM inverter, and examined the influence of the carrier frequency and circuit resistance on the iron loss. We showed that the iron loss increased because of the generation of minor loops when the circuit resistance was high. Therefore, the circuit resistance should be decreased in an actual motor system.

SUMMARYBecause of the development of power electronics technology, pulse width modulation (PWM) inverters are now being used to drive motors in order to achieve precise and energy-efficient control. Precise estimation of the increase in iron loss due to the high harmonic components of flux, including the carrier frequency, is important in the design of motors excited by a PWM inverter. We measured the iron losses of non-oriented electrical steel sheets that were excited using a single-phase full-bridge PWM inverter, and examined the influence of the carrier frequency and circuit resistance on the iron loss. We showed that the iron loss increased because of the generation of minor loops when the circuit resistance was high. Therefore, the circuit resistance should be decreased in an actual motor system. C⃝ 2015 Wiley Periodicals, Inc. Electr Eng Jpn, 192(2): 49-56, 2015; Published online in Wiley Online Library (wileyonlinelibrary.com).