To our valued customer,

“Brush up on Motor Design!” by Prof. Miller, an authority on motor design is available on our website. From beginners in motor design to experts in design and analysis, this content can be of reference to everyone.

In response to requests for subtitles, we are releasing subtitled versions from time to time. You can view it not only in English but also in many languages!

Vol.13 has been released!

[Vol.013] Preliminary Design of a 3-phase Induction Motor (Part 6 : Equivalent circuit; Stator slot-leakage reactance)
This thirteenth seminar is part 6 of designing an induction motor.
The focus is on the stator slot-leakage reactance of equivalent circuits in induction motors. The leakage reactance is the most important concept in the theory of induction motors. It not only determines the maximum torque in the induction motor, but can be said to determine available level of torque at all speeds.
In this seminar, leakage reactance is reviewed and described from the perspectives of both the classical theory and the finite element method.

You can also make inquiries to Prof. Miller if you have any questions.
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We recommend first taking a look at “An engineer’s diary”.

We introduce analysis cases that we received inquiries from customers and are often viewed on the WEB.

276 – Six-Phase IPM Motor Harmonic Iron Loss Analysis


It is necessary to be aware of iron loss to increase the efficiency of motor drive systems. When power is converted using PWM, carrier harmonics produced by PWM are superimposed on the current and IPM motor core magnetic flux density waveforms, causing an increase in iron loss. Iron loss accounting for PWM carrier harmonics can be evaluated by modeling control circuits that include PWM inverters and coupling them with magnetic field analysis.
In this example, confirming the effects of carrier harmonics on the iron loss of a six-phase IPM motor are explained here.

Operating Point to Evaluate

The efficiency map and the operating point for evaluating this motor are shown in Fig. 1.
This evaluates harmonic iron loss at an operating point where rotation speed is 2,800 r/min and torque is 75 Nm. This operating point also has a current amplitude of 76.6 A and a current phase of 36 deg.

Modeling to Account for Harmonic Iron Loss

The control circuit is shown in Fig. 2.
The control circuit is created to account for the influence of the PWM. A JMAG-RT model is used in the control circuit. Calculation is performed with the JMAG-RT model when analysis begins in a transient state. Analysis time is then reduced by switching to FEA after reaching a steady state.

Please see the website for Loss Breakdown and Joule Loss/Loss Density Distributions.

Sample data is available to JMAG proper users and requires license ID to access.
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