Application Catalog
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| 59 - Iron Loss Analysis of an IPM Motor Accounting for a PWM -Direct Link-
<DP,LS> |
Overview
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In the control circuit of a motor, a vector control such as a PWM controller
is generally used. Therefore, to obtain more detailed characteristics of
the motor, it is necessary to take into account the effect of carrier harmonic
in the PWM for the magnetic field analysis. There are three methods to
input a current waveform that accounts for the carrier harmonic in the
PWM in JMAG. A direct link can be established with the circuit/control
simulator, the current waveform obtained using the JMAG-RT motor model
and circuit/control simulator can be input, or the actual measurements
of the current can be input.
This example presents an analysis of the iron losses of an IPM motor accounting
for the carrier harmonic by directly linking to a circuit/control simulator. |
Iron Losses
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The iron losses, hysteresis losses, and Joule losses when the IPM motor
is driven by a PWM inverter and sinusoidal current are indicated in Table
1.
The iron losses in both the rotor core and the stator core increase when
the IPM motor is run using a PWM inverter. The Joule losses increase the
most severely, increasing 70 % in the rotor core, and 40 % in the stator
core. |
Joule Loss
The frequency components of the Joule losses are indicated in Fig. 1 to
Fig. 4. The Joule loss density distribution is indicated in Fig. 5 and
Fig. 6.
The fundamental frequency and harmonic component have almost the same amount
of iron losses in both the rotor core and the stator core, if a sinusoidal
current or a PWM inverter is used when the fundamental frequency is 360
Hz for the rotor core and 60 Hz for the stator core. But, there are more
iron losses produced for the fundamental frequency at 10 kHz and its harmonic
component of the PWM for only the PWM inverter (These values are indicated
inside the green square in Fig. 1 and Fig. 2).
The increased Joule losses when the motor is driven using a PWM inverter
are caused by the carrier harmonic. The effects of a carrier harmonic need
to be evaluated to analyze the characteristics of an IPM motor in detail. |
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Updated: 2011-07-12
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