Design and Performance Analysis of a Three-Phase Inverter for Driving A BLDC Motor Using the Six-Step PWM Method Based on Matlab Simulink

Abstract

This study analyzes the design and performance of a three-phase inverter for BLDC motor drives in electric vehicles using the Six-Step PWM method. The research aims to overcome the low efficiency of conventional inverters (56–57%) by increasing efficiency above 70% while also targeting a Total Harmonic Distortion (THD) level below 5%. MATLAB/Simulink simulations were carried out with a 48V, 1000W BLDC motor at duty cycles of 60%, 70%, and 90%, tested under no-load and loaded conditions. Validation was conducted by comparing the results with a commercial Votol EM-50S controller employing SPWM modulation. The results show that Six-Step PWM achieved efficiency ranging from 88.99% to 98.37%, with an average improvement of 13.60% compared to the SPWM controller (72.01%–84.57%). However, THD values remained very high (61.70%–107.82%), significantly above the <5% target. This confirms a fundamental trade-off: Six-Step PWM offers much higher efficiency but at the cost of poor waveform quality. This work highlights the research gap by directly benchmarking Six-Step PWM simulations against a commercial SPWM controller. The findings indicate that Six-Step PWM is optimal for applications prioritizing energy efficiency and extended driving range, while additional harmonic mitigation measures would be necessary for compliance with strict THD standards.