Diagnosis and Mitigation of Electromagnetic Interference Generated by a Brushless DC Motor Drive of an Electric Torque Tool

Abstract

Electrical devices in the consumer markets need to comply with stringent standards for electromagnetic interference (EMI) distortion and electromagnetic compatibility (EMC). This paper presents the results of measurements of electromagnetic interference generated by an electrical drive of an electric torque tool with a brushless DC motor. The measurements were made in accordance with the PN-EN 55014-1:2017-06E standard, in the frequency band of 148 kHz–30 MHz. The results confirmed that the tested drive can meet the requirements defined in this document. Another document, the PN-EN IEC 61000-3-2:2019-04E standard, provides limits for the harmonic content in the current drawn by electrical devices from a single-phase AC line. This paper also presents the results of measurements related to this standard. Harmonics, up to and including the 40th one, were determined and compared with the limits given in the standard for class B devices. The measurement results indicate a need to use an active power factor corrector (PFC) filter. Such a system has been tested by computer simulations. The results confirmed its ability to meet the requirements of relevant standards.

Keywords

• brushless DC motor
• electronic commutation
• EMI
• EMC
• disturbance diagnosis
• higher harmonics mitigation