#### Abstract

With regard to the pulse width modulation (PWM) of seven-phase motor system if the three-phase space vector pulse width modulation (SVPWM) is simply extended to the seven phase motor system that is the seven phase of the traditional SVPWM it will produce a great harmonic current. In order to restrain the harmonic content of phase current the voltage vector synthesized in the 3<sup>rd</sup> harmonic subspace and the 5<sup>th</sup> harmonic subspace should be zero. Based on this idea the near six vectors space vector pulse width modulation (NSV-SVPWM) algorithm is proposed and the derivation process of the algorithm is given. This paper focuses on the analysis of a novel SVPWM algorithm for seven-phase permanent magnet synchronous motor (PMSM). At the same time the mathematical model of seven-phase PMSM is deduced and the voltage space vector distribution of seven phase voltage source inverter is analyzed. The simulation model of the seven-phase PMSM vector control system is established by using the Simulink tool of MATLAB. The correctness of the algorithm is confirmed by simulation and the purpose of restraining the current harmonic is achieved.