The Noise and Vibration Analysis of BLDC Motor Due to Asymmetrical Permanent-Magnet Overhang Effects

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper relates to a vibration analysis of brushless dc (BLDC) motors using the asymmetrical <formula formulatype="inline"><tex Notation="TeX">$Z$</tex></formula>-axis overhang of permanent magnet (PM). In BLDC motor, the asymmetrical <formula formulatype="inline"><tex Notation="TeX">$Z$</tex></formula>-axis overhang of PM generates <formula formulatype="inline"><tex Notation="TeX">$Z$</tex></formula>-axis thrust, which leads to <formula formulatype="inline"> <tex Notation="TeX">$Z$</tex></formula>-axis eccentric force by commutated current on the rated load and then the <formula formulatype="inline"><tex Notation="TeX">$Z$</tex></formula>-axis vibration. The <formula formulatype="inline"><tex Notation="TeX">$Z$ </tex></formula>-axis thrust ripple, which is the source of <formula formulatype="inline"><tex Notation="TeX">$Z$</tex></formula> -axis vibration under commutated current, is analyzed by using 3-D finite element method, and the phenomena of <formula formulatype="inline"><tex Notation="TeX">$Z$</tex></formula>-axis vibration are analyzed by experimentation. </para>