Harmonic effect on BLDC motor temperature caused by driving system

Abstract

This paper presents the analysis of harmonic effect caused by driving system of the brushless DC (BLDC) motor. The constant ratio of voltage per frequency can result various voltage and current harmonics depended on the modulation index or duty cycle. The losses of the BLDC motor result the rising temperature. The LC filter was designed to meet the BLDC motor on total harmonic distortion reduction. The BLDC motor operates with 40 kHz switching frequency, the experimental of 10 kW BLDC motor was investigated to find out how harmonic and THD can affect the motor loss. Three liter of water was circled as water cooling on the motor. The experimental showed that the operation at higher voltage introduces lower THD, also lower loss, where the LC filter results lower motor temperature compared to without LC filter.