Initial rotor position estimation of SPMSM based on voltage vector injection method

In order to solve the starting failure problem of surface-mounted permanent magnet synchronous motor (SPMSM) at zero speed, it is necessary to estimate the initial position of rotor by using the magnetic saturation effect of motor. In this paper, a new method of voltage vector injection is proposed to estimate the initial position of rotor. First of all, the voltage vector is injected into the A, B, and C phase axes of the motor stator, respectively. Then, the arcsine function of the virtual q-axis response current corresponding to the three injection voltage vectors is solved out, and the average value of calculation results will be equal to the estimated initial position angle of the rotor, which is expressed as Δθ. Finally, two voltage vectors are injected into the two estimated rotor position angles (Δθ and Δθ + π), respectively, and the polarity of the rotor N-pole will be determined by comparing the virtual d-axis response currents at the initial position. At the end of this paper, the proposed method is verified by experimental test, and the average error of estimated electrical angle is about 0.1845^o. As this method has the advantages of not requiring a low-pass filter, reducing system complexity, and quickly estimating the initial rotor position, it has a great application prospect in the initial position estimation of PMSM sensorless control.