Kazuo Ida

3-D eddy current analysis in a silicon steel sheet of an interior permanent magnet motor

Interior permanent magnet (IPM) motors are widely used in various fields. It is important for the high-efficiency operation of IPM motors to clarify the iron loss. In this paper, the harmonic eddy current loss and the hysteresis loss of a piece of silicon steel sheet of an IPM motor are calculated using the three-dimensional finite-element method (3-D FEM). It quantitatively clarifies the effects of the phase difference between the induced voltage and the coil current on the torque and the iron loss (the eddy current loss and the hysteresis loss).

3-D electromagnetic force analysis of effects of off-center of rotor in interior permanent magnet synchronous motor

Interior permanent magnet synchronous motors are widely used as the motor for compressors of air-conditioners. From the viewpoint of the engineering, it is very important to estimate the characteristics of the electromagnetic force, when the motor has an off-center rotor, as well as under the ideal condition. However, the numerical analysis taking into account an off-center is difficult. Especially, the analysis of an off-center such as the rotor tilts is difficult because the analyzed model has complicated shape. Therefore, we developed a method to analyze the model that has the tilting rotor. We clarified the effects of the off-center rotor on electromagnetic force using the 3-D finite element method.

Effects of off-center of rotor on distributions of electromagnetic force

Some of the motors used for compressors of air-conditioners are cantilevered. The noise of the motor becomes louder when the rotor is off-centered. Therefore, it is important to analyze the motor with an off-centered rotor in order to reduce the noise from such motors, because it is not easy to measure the degree of the off-center in experiments. In this paper, an interior permanent-magnet motor with the off-centered rotor is analyzed using the three-dimensional finite-element method. Consequently, the effects of the off-center of rotor on the electromagnetic distributions and those harmonic components are quantitatively clarified.

Analysis of magnetizing process using discharge current of capacitor by 3-D finite-element method

When permanent magnets are magnetized using the coils in the stator of a motor, it is very important to be able to estimate the residual flux distribution in the permanent magnets. Therefore, we have developed a method to calculate the residual flux distribution using the three-dimensional (3-D) finite-element method taking into account the magnetizing process that uses the discharge current of a capacitor. We have also analyzed the effects of the eddy currents in the permanent magnet during the magnetizing process on the residual flux distribution. The accuracy of the method was confirmed by a comparison between the calculated average magnetization ratios and the measured ones.

Three-Dimensional Loss Distribution Analysis of an Interior Permanent Magnet Motor Driven by PWM Inverter

We analyzed an interior permanent magnet motor (IPM motor) driven by the PWM inverter using the three-dimensional finite element method (3-D FEM). The distributions of the eddy currents in the permanent magnet, and the iron loss characteristics were quantitatively clarified