Asymmetrical Six-Phase Space Vector Pwm Scheme

Abstract

Multiphase electric motors have smaller torque pulsations and are more reliable that their three-phase alternatives. However, standard electricity grids around the world are three-phase, so power inverter is needed to drive multiphase motors. Inverter is used not only to power the motor, but also to control the am­plitude and frequency of the produced voltage, thus controlling motor speed and torque. Multiphase systems with odd number of phases have been widely investigated; therefore, this paper focuses on a six-phase inverter with a single neutral symmetrical load. A novel asymmetrical space vector modulation scheme is proposed and evaluated using simulations in Matlab/Simulink. Simulation results are compared to other modulation schemes. The proposed method is suitable for generating near-sinusoidal output voltages; however, it might not be suited for driving motors with sinusoidally distributed stator windings.

Keywords

• large and medium space vectors, six phase inverter, six-phase motor, asymmetrical SVPWM.