Abstract: In order to suppress the third harmonic current in stator winding of the nine-phase open-end winding permanent magnet synchronous motor (PMSM), a harmonic voltage feedforward control method is proposed in this paper. The third harmonic voltage caused by non-linear factors of the inverter is tracked by synchronous reference frame phase- locked loop (SRF-PLL), and the third harmonic voltage of the back EMF is also considered, which both are used as feedforward components. With the combination of voltage harmonic feedforward control and current harmonic closed- loop control, response speed and control accuracy of the third harmonic current control are improved. Finally, the feasibility and effectiveness of the third harmonic current suppression method proposed in this paper are verified by experiments.