Overview
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The relationship between the current and torque is a fundamental characteristic
of motors. The torque produced by the current increases linearly as the
current increases up to a certain point, but the torque produced by the
current decreases by the magnetic saturation when the current is increased
further. Understanding the current versus torque characteristics using
simulation is beneficial for examining the motor design and drive state.
This example presents the use of a magnetic field analysis to obtain the
current and torque characteristics that are fundamental to SPM motors. |
Magnetic Flux Density Distribution
The magnetic flux density distribution for a current amplitude of 10 A
and 200 A are indicated in Fig. 1 and Fig. 2.
The flow of the magnetic flux changes according to the size of current,
such as in the teeth the magnetic flux density is high. This is because
the teeth are magnetically saturated and the variations in the magnetic
flux pathways affect the torque. |
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Current vs. Torque as well as Current vs. Constant Torque
The current versus torque and the current versus constant torque characteristics
are indicated in Fig. 3 and Fig. 4.
The ratio the torque produced by the increasing current decreases as indicated
in Fig. 3 and Fig. 4. This is caused by the variations in the flow of magnetic
flux indicated in Fig. 1 and Fig. 2. |
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