Impact of PWM control frequency on efficiency of drive with 1 kW permanent magnet synchronous motor

Abstract

Purpose

This paper aims to present the impact of Pulse Width Modulation (PWM) control frequency for specific Permanent Magnet Synchronous Motors (PMSMs) on the efficiency of the entire driving unit. Examinations were carried out for a PMSM unit with a power of 1 kW, rated speed of 1,000 rpm, and rated torque of 6 Nm.

Design/methodology/approach

The PWM frequency ranged from 4 to 20 kHz with increments of 1 kHz. Measurements were taken for each of the foregoing frequencies, for the different load torques, and for the different rotation speeds including overspeed. The results achieved allow the PWM control frequency to be properly adjusted for each PMSM to operate the entire driving unit in the most efficient way and, in consequence, save energy consumed by the drive.

Findings

Obtained results may be used as a kind of background for the design of drive system.

Research limitations/implications

For a specific PMSM-based drive system, one can find the optimal PWM control frequency. This frequency depends on the rotation speed and torque of the motor. However, the validity of the results presented in the paper is limited. They are valid for the specific motor drive under test and cannot be generalized easily.

Originality/value

This work shows that there is some maximal efficiency of the entire system depending on the rotation speed, load torque and switching frequency of the power transistors. For a specific motor working in a certain condition, we can find the minimum power loss.

Citation

Rudnicki, T., Sikora, A., Czerwinski, R. and Glinka, T. (2018), "Impact of PWM control frequency on efficiency of drive with 1 kW permanent magnet synchronous motor", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 37 No. 1, pp. 307-318. https://doi.org/10.1108/COMPEL-01-2017-0031