This application provides a permanent-magnet synchronous machine control method and device, and a permanent-magnet synchronous machine control system. The method includes: obtaining a d-axis current id and a q-axis current iq in a permanent-magnet synchronous machine control loop at a current moment; obtaining a fifth-order harmonic current id5th and a seventh-order harmonic current id7th in the d-axis current id in the permanent-magnet synchronous machine control loop at the current moment, and a fifth-order harmonic current iq5th and a seventh-order harmonic current iq7th in the q-axis current iq in the permanent-magnet synchronous machine loop at the current moment; determining a d-axis current idk+1 at a next moment in each switch state; determining a q-axis current iqk+1 at the next moment in each switch state based on the first current idk, the second current iqk, and the second voltage in each switch state; and determining a control policy of the permanent-magnet synchronous machine.